Fertilization Strategies

Personally, I think you should be changing 50% weekly. Especially if you are using the EI method. You reset your tank each week by doing 50% changes.

This could also be the cause of your algae issues. By not changing 50% of the water, you will still have too much nutrients in the water and your plants can't absorb it, which would cause the algae to flourish. Just a thought...

 

And my previous post (the link) explains in detail the argument that too many nutrients does NOT cause algae...

And if I have BGA I have too little, in fact! Yes I know caused by the 2 x 80% WC.

 

I posted earlier a short reply because I had limited time. I agree I should be doing 50% WC, but my current container only allows for 30% water to be matured. I am looking into options for a bigger container.

The fact that not all the nutrients are absorbed by the plants is probably due to not enough plants. This is in relation to the light level. I have now taken my all the large Ceratopteris I removed (which I had to do because they got out of hand) and planted them in the corner just for the sake of having a larger plant mass while some of the ones I want to keep are still filling in.

Also, I don't dose EI. I use Prof's Drops with added KNO3. I have not been adding the KNO3 religiously, but I think this provided me with a good reason to actually use MCI and find out my tank's consumotion point, seeing as I started this week off with basically no nitrate in the water.

 

I want to get this thread back on track. It is about fert strategies and thought processes and not about personal tank problems, although personal experiences shared can be helpful in this dicussion.

I now read that last link I posted a few times and I've come to a conclusion:

Plant growth and Algae fighting are 2 different things, yet somehow related.

Algae:
1. Barr is adament that nutrient limitation will not resolve algae problems
2. Algae are not limited by CO2 and nutrients. There is plenty coming from fish and enriched substrates, so why try limit dosing?
3. Best thing to do is limit light, which is the easiest way to control things
4. Slow down the tank and fix the issue

Plants:
1. He criticises PMDD (Sears/Conlin) and MCI saying both methods are ways of limiting PO4 in order to fight algae
2. This works, but in a tank with fish you cannot successfully limit PO4
3. So rather dose lots of nutrients and ensure there is no shortfall of anything the plants need
4. Up the CO2 if you can
5. Limit the light. He claims he can grow beautiful red plants using this method and much lower light than some others. This also slows down the demand for CO2 and makes this aspect easier to manage.
6. He quotes examples in water ranging from 1kh to 10kh
7. He quotes examples where he dosed lots and lots of nutrients and had no algae

For him the focus is on growing the plants well, and the algae will be sorted automatically. He also claims that NH4 is a major factor in algae breakouts, needing small amounts to cause algae. Dosing high amounts of NO3 or PO4 will not cause algae IF THE CO2 is above 25ppm.

Then he continues to critisize the PH Controller. I would like some comments on that. He says it is very much dependant on your tap water's kh. So if you have a KH of 3 you would set the controller to ph6.6 in order to get 25ppm CO2, which is a good level to be at. But what if suddenly your tap water changes to 4kh? Your controller is still set to 6.6, so now your CO2 level is 30ppm. Next week it changes to 5kh. Suddenly CO2 is at 37ppm. See where this is going? Do you have to measure kh of tap water before each water change? I think you may have to. Yes I understand you only change 50% of the water so if the tap changes from 4 to 5 then the tank will only change to 4.5kh, but I am trying to illustrate Barr's point here why he is sceptical about using a ph controller for CO2 injection. The so-called set and forget method is not so simple.

Perhaps this is why many people are killing livestock with CO2. Nobody can really be sure what their CO2 levels are, and it is far more dangerous than KNO3 or KH2PO4 that we dose, not so?

So in the end I am wondering once again: what is the goal? Should you wish to primarily keep fish, then probably you should have low to medium light and keep cabomba, swords and hygros without any CO2 injection. Only dose some traces once in a while.

If you want to keep more exotic plants, then be prepared to inject CO2 and dose lots of nutrients. Light can be adjusted as needed. Fish - well I don't know how many can be successfully kept. I believe in such a tank the best thing to do is keep some shrimp. They are much more sensitive to CO2 than fish and will be your first indicator. Push the CO2 as high as you can without upsetting your shrimp. Then you'll be fine.

Regards
Lauré

 

Hi Lauré,

As I mentioned earlier, I have been inundated with lectures and without the time to reply. However, things are easing up a little as a result of which I do have some time to reply this evening.

I also mentioned that I was experimenting with some new fertilizer mixes according to the EI formula and in spite of my heavy lecture commitments I have been running a number of experiments of a number of aquaria using these fertilizer mixes with very different and very unexpected results and I want to tell you about these.

For the purpose of these discussions, I must mention that I used my standard Dirk's Drops ferts which consist of plant hardening mix which I advise to be added at 10 ml per 100 l. This results is 4 degrees general hardness (dGH). At the same time, I added the second component of my standard Dirk's Drops, my plant feeding mix, which is a extensive and balanced trace element mix. I have now also formulated an EI type fertilizer which contains nitrate (N), potassium (K) and phosphate (P). In these mixtures I used potassium nitrate (KNO3) and then not only KH2PO4, but a balanced mixture of KH2PO4 and K2HPO4 which gives a pH of 6.8 and not the acidic KH2PO4 which will cause an unwanted drop in pH. I formulated mixes in which the ratio of N was the what I see is used in EI and which I will refer to as the "standard" EI which was 10:1, then a mix in which the N ratio was 15:1 (which one could refer to as a NPK mix, because it contains all these elements) , and a solution of only KNO3, in other words only NK and no P in this mix. I refer to this mix as NK-P.

Abbreviations used: green algae (GA), blue green algae (BGA), brush algae (BA) and spirogyra algae (SA).

Then the experiments:

1. Tank 1, my lounge tank: tank dimensions: 1.85 m long, 60 cm wide and 50 cm deep, total tank volume around 500 l; substrate only silica gravel. lighting: on one side a 125W mercury vapour lamp, on the other side a 80 W mercury vapour lamp. Plants: About 50 sword plants of which the largest submersed plants have leaves that are 60 cm long and two Echinodorus cordifolius that grow right out of the tank and are about 80 cm tall. Some additional plants: Cabomba, Heterandra, Ludwigia, and some surface Riccia. Fish: heavy fish load which many adult angels and 2 large feeds per day which should result in N and P release. I performed a number of different fertilization regimes and achieved the following results:

A. 50% water change and then standard Dirk's Drops and 10:1 N EI dosing of the recommended dose 3 x per week. Result: Large impovement in plant growth and color of leaves much darker green. In the low light portion of the tank GA within hours after addition of the first dose of NP solution. Less algae in high light portion particularly in the shallow parts of the tank in which the light intensity was higher.

B. 50% water change and then standard Dirk's Drops and only N dosing (NK-P) at recommended dose of 3 x per week. Result: Still improved plant growth but in the low light portion of the tank, much more delayed GSA, in high light portion also more delayed GSA. However by the end of the week GSA on both sides of the tank.

2. Tank 2, Dimensions 50 cm long, 20 cm deep (water depth although tank height 25 cm), 25 cm wide; substrate: Palm fibre peat enriched with Chemicult (traces and low levels of NPK) covered with a 1 cm thick layer of fine silica filter sand. Lighting: A HOPOR 24 w double fourescent light which looks like a sort of "warm white" light, in my opinion a relatively high light tank. PLanting: only Cryptocoryne species, about 20 plants. FIsh load low and two feedings per day.

A. 50% water change and then standard Dirk's Drops and 10:1 N EI dosing of the recommended dose 3 x per week. Result: Large impovement in plant growth and color of leaves much darker green. This is the first time that I have been able to grow Crypts really successfully. Absolutely NO ALGAL growth. I have continued with the regime for four weeks now and have reduced the number of NPK dosings and the crypts continue to grow well.

3. Small tank on windowsill in FULL SUN for 8 hours per day. Without any ferts the plants pearl O2 during the day in spite of corner filter with aeration (which is supposed to remove all CO2, but the plants still pearl O2 indicating that they are taking in CO2). Tank dimensions: 25 cm long, 20 high, water 18 cm deep, 20 cm wide. Planting: Sagittaria subulata growing in a carpet on the floor of the tank, a few floating plants, Pistia stratoides. NO FISHES.

This tank has always had an infestations of a threaded green algae. When examined under the microscope this appears to be a Spirogyra algae which is typical green thread algae.

Prior to starting with the ferts, no ferts were given for weeks on end and the plants were just more or less "hanging in". The SP was a pale sickly green and only just growing.

A. 50% water change and then standard Dirk's Drops and 10:1 N EI dosing of the recommended dose 3 x per week. Result: Some impovement in plant growth, not so much the Sagittaria, but a big improvement in the floating plants and color of leaves much darker green. Massive improvement in the growth of the SP, but no other algae.

B. 50% water change and then standard Dirk's Drops and EI dosing of only NK-P the recommended dose 3 x per week. Result: Large impovement in plant growth and color of leaves much darker green. Still massive improvement in the growth of the SP, but no other algae.

What can I conclude from these three experiments?

1. In higher light aquaria, EI can be used with large improvements in plant growth, but as soon as the light is limiting you will run into algal problem, regardless of standard NP ratios or if only N is added.

2. Different plants have different nutrient requirements particularly with regard to macrocutrient requirements and plants such as crypts which are known to have high phosphate requirements benefit massively from addition of standard EI additions, but enough light is essential.

3. Even under high light, many algae such a thread algae, Spirogyra, and I think Cladphora as well, will benefit massively from EI additions whether they are rich in phosphate or not or whether they contain nitrogen only, these algae just simply will compete with plants for these nutrients and will grow regardless.

What can we perhaps deduce from these results?

1. EI should only be used in high light aquaria. Under too low light conditions the excess phosphate and nitrate will stimulate GSA growth.

2. Different plant combinations will demand different amounts and ratios of NP and N only (in other words need NPK ferts or only NK-P ferts). Any excess of N and P will result in algal growth.

3. Thread algae will grow irrespective of EI additions and will compete for nutrients with plants. They are actually more closely related to plants than any other algae. My opinion on these algae is that in order to get them under control you will need to use anti-algal medications to kill them off, and once they are gone then only the plants can use the EI additions. The implication of this is that with every import of a new plant we are potentially importing a new algal species. I think that in all of these discussions about algae this is completely ignored yet it is absolutely critical.

Final conclusions:

These are the results of my experiments with my Dirk's drops ferts in combination with EI. It is obvious to me that EI can have massive benefits in planted aquaria, but only under high light conditions. Under low light conditions, plants can get enough nutrients from trace elements additions and from the waste products of fish, but as soon as we increase the light, the plants outstrip the supply of N and P from the fishes. In order to compensate for this N and P should be added, but it should be added in the ratio as required by the plants, in some instances more P together with N and in other instances less P but still enough N. If the ratio is not right, this will result in GSA. As a result, every aquarium will differ, with regard to light, combination and load of plants, and fish load, as a result of which, I have come to the conclusion that one needs to be able to adjust the requirements of each tank individually. Some tanks will require high N and P and other tanks less P and more N. A basic requirement is however enough hardness (a dHG of not lower than 4) and trace elements in optimal ratios.

As a result I will now adjust my plant ferts as follows:

1. A hardening mix, which should be added according to your water hardness. Cape water = very soft = full addition; Gauteng water harder = measure hardness = add hardening mix only if hardness less than 4 dGH.

2. A traces mix which is essentially my unaltered plant feeding mix as I call it, which needs to be used regardless of plant species, lighting, or fish load.

3. A NPK mix of which the N ratio is 15:1.

4. A mix which I will call NK-P which contains Potassium nitrate only (KNO3).

I would then recommend the use of the hardening mix to get to at least 4 dGH and the trace mix as a constant addition (both added after a water change). Then I would recommend that the NPK mix be used in lower amounts than standard recommended EI additions (which are three times per week) and I would monitor GSA algae closely. If it grows, use NK-P to reduce GSA and eventually work out a optimal amount, not too much to cause algal growth, but enough to cause good plant growth.

During this experimental phase, I have been supplying my fertilizers (hardening, traces, NPK and PK-P) to other members of this forum and perhaps they can show their (very good) results or refer to their threads with my fert mixes as well.

In future, I will therefore adjust my offer of ferts to the following products: Plant hardening mix, plant feeding mix or traces, NPK mix (N ratio 15:1) and NK-P mix containing no P.

I think this is the longest post on TASA ever and Lauré, I think this should give you enough to think through this weekend!

Kind regards,

Dirk

 

Prof Dirk

I also have some time this evening to actually sit down and respond to a few things. Firstly I want to ask if you have considered adding DIY CO2 to one of these experimental tanks in order to see if the algal growth is not possibly caused by excess nutrients, but rather by a CO2 limitation for the plants. I know we have had the discussion before, and your tank in the window with O2 pearling indicates there is some CO2 in the water already, but perhaps not enough?

Reason why I say this is when one goes and reads all the posts on EI, one thing is clear: CO2 levels are always discussed. Now in the states and parts of Europe we know hard water abound, so those guys need to add CO2. In the link I posted just earlier Tom Barr talks about his experiments and they include tanks with a very low hardness (1dKH). He still adds CO2 as a starting point. So if the EI guru is so obsessed with CO2 injection, then it might be worthwhile investigating the effects of CO2 injection when performing your new EI-style dosing.

I would just really like to see a controlled experiment with your new ferts where CO2 can be added, even to soft water, just to see how the algae growth and plant growth is affected. I fear that I do not have such facilities available, but perhaps you can find the time to try this out?

The with regards the light, I note that your findings above are in direct contrast with Tom Barr. He claims that he gets great growth in medium light, BUT with added CO2 up to 30ppm. He prefers to use light as a limiting factor. In other words, up the dosing, up the CO2 and control things with light, which he says is the easiest element to control of the lot. But then again, one person's opinion of high light might be another's opinion of medium light. With my 4x 54W T5 lights I thought I had high light, until Christian Rubilar (MCI) told me I do not have enough light for a tank over 40cm deep. He says I need metal halide.

Back to the dosing. EI does make sense in a way - why would you want to limit P as a way of controlling algae? You can do this in a tank with no fish or low fish load, but medium to high fish load you will never successfully limit P. I think another part of the puzzle is that P is related to CO2 uptake. So if there is enough CO2, then high P won't be available to algae, right? And you can drive the speed of this process by varying your lights.

On this topic, I noted that plants from the Americas are mostly high N demand plants and those from Africa and Asia high P demand. This is a generalization, but seems to hold true for most of the popular plant species we keep. So we have to consider this when choosing plants and dosing regimes.

The other subject I want to touch on just quickly is the dosing of additional Fe to the water column. There is apparently a misconception that Fe excess is linked to certain types of algae and high Fe dosing actually just results in better growth for certain plants, not additional algae. Barr proved that these particular algae types, often identified as triggered by Fe, actually are triggered by NH4 and NO2.

I have also found that I only ever get thread/stringy algae in very high flow areas. When the flow is brought down, they go away after a week or 2. Maybe just coincidence?

Then I believe you touched on a very important point and that is the concept of quarantine for new plants. We do it with fish to avoid infections in our tanks; why not with plants to avoid new algae? You are right and I agree that lots of algae spores are brought in with plants. We should formulate a way to "sterilize" the plants. I have seen many, many articles about the bleach dip or even potassium permanganate, but I am rather uncomfortable with either. Another one is H2O2, often used to kill algae.

I will have some more comments at a later stage. I think I want to read your post a few times, think it through and then I'm sure I'll have some more questions.

Regards
Lauré

 

Hi again

I am now going to ask some specific questions and make some comments.

When you say GA do you mean Green Algae, such as soft green fluffy growth on glass and plants, or do you mean GSA (green spot algae), which is the hard dots on the glass? I guess you mean the latter, and GSA is a clear indication of too much N. This is the only algae type which grows under high N. Also, I have never seen it grow when the light is medium to low. In my research on these algae types it was confirmed that it grows in high light with high N. It needs high light, so I find this very, very strange.

Now I am starting to think you don't mean Green Spot Algae. What I conclude from the above is that you only dose N, so your N ratio would be in favour of N. You would in this case see much more GSA and much quicker than if you also dosed P. Tell me you don't mean GSA because then I am totally confused...

Is the spirogyra still growing? Can you try to lessen the water flow and see what happens?

I can buy this. Low light = low growth rates = less demand for nutrients. Whatever is available in the water column is now available for algae. In Barr's writings on EI he always increase CO2, which also results in high nutrient demand. Hence he can "overdose" macros, and control uptake rates with light. Without injecting CO2 one probably cannot maintain a low to medium light tank and still dose heavily.

Absolutely. I think the key is to find a balance in your species planning. Keep some stargrass (high N deman) and then a Marsilea carpet (high P demand) and you should be OK, or does this not make sense? Or else, keep a tank with only crypts and then dose more P than you would in a tank with only swords.

I would like to think we can possibly rule out nutrients as the CAUSE of algae growth. Limiting P is successful if you don't have any fish contributing P. But most people do, so now you have to bring the whole lot up a notch in order to create a balance. The actual cause of algae growth is poor plant growth. Why is it often said healthy plants will outcompete algae? This is why Barr says FOCUS on the plants, give them what they need, the algae will stop blooming when the plants are growing well. Many others, like Cristina Rubilar from MCI, says something very similar. They are both of the opinion you can have a nice tank with good growth and no algae. It is about finding the balance. They just each go about it in a different way.

And please note, I am not necessarily a fan of Tom Barr, I just mention what he says because much of this discussion is around EI. There are plenty of other people with very valid arguments.

Regards
Lauré

 

Prof Dirk

With respect to my Fe question, perhaps you could take a quick look at this thread?

http://www.barrreport.com/co2-aquatic-plant-fertilization/6203-fe-uptake-active-fe-plants.html

Tom Barr also reference links to some scientific papers on the topic. Perhaps this thread will be of some value? I can only imagine that if you increase macro dosing you may have to increase micros, possibly at least Fe?

Regards
Lauré

 

Hi Lauré,

A quick answer during a late tea time break in between my Saturday gardening.

With regard to your iron question all I can say is that the iron levels in my ferts are far higher than those mentioned in the Barr article, so I do not think iron is limiting here.

To get to your other comments and questions I want to say that I have approached this in a different way. I produce my ferts and then I get questions or in some cases accusations from users as to why algae grows in their tanks and why their plants do not grow as shown on the Tom Barr websites and others. The bottom line is that there is a lot more to it than just adding ferts which the user must try to sort out. From this perspective, I then said to myself, "can I use the standard EI method of adding three additions of NP containing ferts per week in addition to using my ferts and expect those results". From my experiments I must conclude that you cannot do this just like that. You need to carefully add some of these components, either NPK or NK-P in much smaller amounts and with larger intervals in order to try to tune your aquarium to the use of these additional macro ferts.

However, there is no doubt that you get vastly improved growth even with less than full EI additions. So, in my opinion the problem is not poor plant growth. If you look at my swords there is no sign of poor growth they are growing very strongly and as I say if I use the standard EI additions on that tank, the algae gets cumulatively worse in other words as I progress to the "end of week" at which you are supposed to do the big water change to get everything back to normal, the algae continues to grow even more strongly. I have also purposely not done the water change and in the second week not added any nutrients, both micro and macro and then the algae DOES GET LESS, so the plants are using the nutrients and the algae cannot use them for their growth.

On the Spirogyra algae the growth is good regardless of whether you add just N or N plus P (and there is a minimal current in that tank, just to answer your other question), so these algae, which often overgrow polluted water systems are doing exactly that, they are enjoying the extra N or N plus P and are growing gloriously. I want to now try to kill these algae with an antialgal and then see what will happen after that.

I have not discussed additional CO2 fertilization because I first wanted to comment on systems without CO2. The reason for this is because CO2 addition is expensive as the regulators and cylinders are expensive and need careful maintenance. Homebrew CO2 in the long run is a schlepp, but for those who cannot afford it this may then be a weak alternative although then CO2 must not be added at night due to pH fluctuations which are negative for the fish.

So, what happens if you add CO2? Well someone else on this forum (the stig) has done these experiments for me and we are getting stunning results. You add the hardening mix to 4 dGH, add my standard amount of traces, and then you can add three additions of my NPK mix or NK-P mix per week and work with the weekly 50% water change and off you go. You get luxuriant plant growth and you need to carefully tune the NPK and NK-P usage to get the algal control just right, but it works! So your comments about CO2 are correct in that its addition gives massive improvements, but I do not want to go down the route of trying to explain why, because this all gets too unscientific. Without proper measurements we are guessing about the reasons and this just generates rumours which are counterproductive. Bottom line is, and I am quite excited about this, one can achieve excellent plant growth with my original drops in combination with EI mixes and CO2. I still want to formulate a mixture with which one can increase the KH just enough to be able to use CO2 in our soft water, but I am in the process of developing the first prototype solutions and as these types of solutions are well known, I see no reason why they should not work.

Kind regards,

Dirk

 

Hi Prof Dirk

Hope you enjoyed the gardening, and as a Province man, probably not the rugby...but I am happy as a Bulls man! Now back to the topic...

This is assuring to know. I am then going to continue using your micros at 10ml per 100l every WC and not worry about measuring Fe levels.

Absolutely agree. Good cleaning of tank and filters, watching things, taking notice, learn to "read" the tank, etc.

This might be the key. What you said above is similar to what Barr says with respect to controlling an algae bloom. Get the tank moving slowly at first, by adding less light and possibly less ferts (although Barr never mentions less ferts), and then over a period of a few weeks accelerate this process up to maximum levels.

Can one conclude from this that the amount of ferts in the water is then probably more than what the plants can take up? Leaving enough for algae to flourish. Which is why Christian Rubilar and Tom Barr continue to argue on these forums. Barr says add the ferts; Rubilar says add only enough for the plant mass, in other words, find your tank's consumption point.

I have a friend returning from London in December. I can get a very good brand new regulator, ph controller, check valve, Co2 tubing and glass diffuser for a total of R1000. Prices are coming down in Europe. Yes, this is still a sizeable expense, but one must then ask is this worth it? Of course, the gas cylinder I can pick up locally for about R500, so I need to ad that to the list. I am toying with this idea, but I am not sure yet.

I have a 3ft guppy tank which is also planted quite heavily and in this tank I have DIY CO2 with which I have been experimenting for a few months. I also have lots of ramshorns and absolutely no algae, despite the fact that it gets a serious whack of sunlight during the afternoon.

Will we see pics on here soon?

Regards
Lauré

 

Hi Lauré,

Thanks for your reply, which I appreciate because you highlight precisely that each one of us that want to have a perfectly planted tank need to put in a lot more effort than just adding ferts and supplying light and perhaps CO2. A perfect planted tank requires a lot of effort and fine tuning.

Well, the gardening was good, the performance of WP was less so....

I would like to support this fully. Algae are either single celled organisms or primitive multi-celled organsisms which mostly have each single cell in contact with the water. This means that absorption of nutrients is fast in these cells.

By contrast, plants are multi-celled and cells on the inside of the plant would only receive the nutrients from the cells on the outside of the plant that have absorbed the nutrients. I believe this will take longer than in algal cells as a result of which the absorption and the effects of ferts on plants must be more delayed than in algae.

Well, the million dollar question is who is the stig and has she/he already posted pics on this and other forums...... now you must just identify who she/he is.....haha! We will reveal this in due course as we still have a few minor experiments to perform, but so far the results are stunning.....!

Kind regards,

Dirk

 

Hi Prof Dirk

And Hi to everyone else reading this thread. I just realised I have only been addressing the Prof and I really intend for this to be an open thread, not just a discussion between 2 of us.

And this is why for example Green Spot Algae (GSA) is such a good indicator of NO3 levels. The moment there is excess (and by this I mean more than what the plants can use), you get instant GSA. As I've said before, hobby quality test kits are unreliable. Algae don't lie. And the amount of GSA and the reaction time is directly related to the amount of light. Using GSA as a bio-indicator, it is quite clear why this works better with high light, because then you catch it instantly and can react.

Let's summarise quickly 2 of the most popular methods:
EI - add lots of ferts, lots of CO2, use light as the limiting factor (the accelarator pedal)
MCI - add lots of light, lots of CO2, use nutrients as the limiting factor

Which one works better? Perhaps that is the million dollar question...

Now we just wait for the promised pics!

Regards
Lauré

 

Evening all,
I would like to go in another direction and start in the begining.What I mean is when you first set up your aquarium.The substrate.
How important is it?Is it just a rooting medium or a source off noutrients,fertiliser.What is the best to use,sand,soil or the branded comercial stuff.And lets not get sidetracked and get ficsated on Seachem Flourite,there are other, less ecspensive, materials out there.For exsample,cat litter.
Why not explore this side off Fertilisation strategies.

 

Hi Lauré,

A few quick comments:

You say that GSA is a good indicator of nitrate levels, I also think that it is a good indicator of phosphate levels as well. I cannot see how we can exclude that deduction without showing this by actually measuring N and P levels.

On the pics...... I did not say that they still needed to be posted......

Rudi,

Nutrients can certainly be added by means of the substrate about that there is no doubt. However, unless properly defined they are more dangerous than good, and by that I mean things such as "rose compost" or any compost for that matter can vary so much that we cannot make any comments about the use of this. I do not know what cat litter is made of but I would be careful as much of it looks like burnt ash, possibly a waste product from coal burning and if it is that it will be full of toxic substances. Seachem flourite is supposed to be good (I have not used it because of the price as well), but you can dissolve a certain amount of Chemicult, one of the types that contain lower nitrogen levels and then use this to be soaked up by a palm fibre peat brick and use this in the substrate with a layer of silica sand over it. However, for fast growing plants, the nutrients that the plants obtain directly from the water cannot be replaced by feeding from the medium, they simply need too high levels of nutrients for them to be supplied from the medium only.

Kind regards,

Dirk

 

Perhaps I didn't express myself correctly. GSA is a good indicator of NO3 excess when compared to PO4. GSA is the only algae that blooms when this condition is true, IF you have enough light to support its growth. It also appears very quickly when this condition is true and is a good bio-indicator. Which is exactly why MCI aims to get the tank fertilized until this condition is reached. Then you know where you are. Rubilar says it's like the blind man with a stick walking next to a wall. As long as he knows where the wall is, he is fine. So, when you have GSA, your NO3 levels are more than what the plants can consume. You can increase other elements (light, CO2, PO4, traces) to correct the balance, or do a WC to reset the NO3 levels. Sorry for not being absolutely clear.

The suspense is killing me. I think I'll have to go and search some threads. It must be a Cape Town forum member... :bigsmile:

Regards
Lauré

 

Natural kitty litter is made from clay and silt. It generally has good cation exchange capacity, but that's it. On that basis alone you cannot compare it to flourite.

 

Hi Lauré,

OK, I get it, that sounds pretty understandable to me. I will try to run some experiments with even lower nitrate fert levels and see if this will not induce the GSA and then report back.

Kind regards,

Dirk

 

Prof Dirk

Now that I am back at work and have a little bit better access to some web resources I want to post a few comments on the above.

You are referring to Spirogyra, this one? http://aquariumalgae.blogspot.com/2007/06/blog-post.html

I was, in my reply, referring to this one:
http://aquariumalgae.blogspot.com/2006/03/thread-algae.html, which I get in high-flow areas. I find it impossible to kill, because if I drop the outflow level it goes away by itself, but then I feel I do not have enough circulation. It only grows on plants that are tall and directly in front of the spraybar outflow, which is submerged about 8cm under the water level.

Regards
Lauré

 

Hi Prof Dirk

Any ideas on what you would do to enrich inert substrates that are already in use? In other words, a tank with silica gravel and fish already and also planted and now there may be a need to have a richer substrate. What about something like http://www.osmocote.co.za/

The idea of a rich substrate is that it supplements the water column dosing. I think one can get away with only water column dosing for the most part, but a few plants such as crypts are heavy root feeders and will probably do better in a richer substrate. Many other stems plants are fine with an inert substrate, but do even better with a richer substrate. Same goes for most of the popular carpet plants. Specifically if the roots have access to NO3, PO4 and possibly NH4 in the substrate.

ADA Aquasoil contain the above and yes it does leach some ammonia into the water column during the first month. Which is why you are advised not to add fish for at least a month.

Most of the other brand name substrate contain mostly just iron and I can't see why I would spend that much money on things like Flourite just to get an iron benefit. For iron, I use nails, and its much cheaper.

Regards
Lauré

 

Hi Lauré,

As you quite correctly indicate, there are some plants that do better on an enriched substrate and if fed only via the water column they do not do that well. One of my favourite group of plants are Cryptocoryne. You have to be patient with these as they take a long time before they form mature stands but there are very few plants that have the elegance of crypts.

With this in mind I have been doing some experimenting over the past years with regard to the addition of nutrient enriched substrates. The first enriched substrate that I steered away from completely were the garden composts as they do not have a standardized composition so you just simply cannot rely on them for consistent results. I also grow a considerable number of garden plants in pots as a result of which I have experimented with many substrates. One such medium is palm fibre peat. This is in actual fact not peat, but is coconut husk which has been ground up and then compacted into a brick shape and which can be bought from many nurseries and garden shops. When one uses this for growing plants, you put water into a bucket and then you place the palm fibre peat brick into the bucket overnight. It then absorbs the water and amazingly the palm fibre then fills almost the whole standard bucket with a nicely loose substrate. Firstly this substrate has the advantage that it is relatively inert and only rots over a period of years. Secondly, and this is the important point, one can prepare a nutrient solution in the bucket and then one can add the palm fibre brick and it draws up all the fluid into the fibre. I have added the basic chemicult to the water and then added the brick to draw up the fluid. I have then put a layer of this under fine silica filter sand and planted by crypts onto this mixture about 6 months ago. I have fed the crypts with my standard ferts as well as my soon to be released NPK additives and the crypts are growing magnificently. An important point is that I do want to point out that the palm fibre peat is called "peat" but that it is not really peat and it does not have the acidity of normal peat which is a very important consideration in soft water aqauria.

This however only partially answers your question as one actually cannot add the palm fibre peat to an established aquarium as some of it floats, and it would be difficult to place in a specific position. What you could consider is to drain an established tank completely, and then to add the palm fibre peat to the substrate, cover it and then fill up the aquarium again. You could obviously do this with the water that comes from the tank. This is perhaps not an entirely easy solution, but is not impossible.

In my German magazine, the DATZ, I see that a company now offers the clay balls that have been used for a long time and which essentially only add iron, but these have now been enriched with NPK for feeding as well. I think this actually makes a lot of sense and these clay balls could then very easily be added to an established aquarium without having to re-establish it and may be the solution to your problem.

Kind regards,

Dirk