DIY Overflow and sump Using - Professor Dirk Bellstedt Designs

Good Afternoon Professor, thank you for the input, yes I am/was aware the filter you designed was made in the side section of a tank (next to it or part of the tank)
But the flow rate and oxygenated water to filter media theory is solid and should work better then a traditional baffle design of a sump ?
With a small little modification it seems to make an excellent sump ?

Overflow, this was one of those steps that I had to make the mistake of doing it the wrong way before I did it your way (My stubborn nature)
My theory was closing pipe end "1", creating a sealed system = a siphon to rid the pipe system of air then breaking the siphon by opening "1" again, and having a working overflow. It worked but it took some difficulty starting a full siphon, much much much easier adding the airline to remove the air.

I have built the sump using an exiting fish tank so all measurements have been changed and the breath is of-course allot wider then your original design and @Zoom suggestion of a lower plane to avoid overflowing the sump.

My apologies if this has caused any confusion, my only intention was using the base of your design and converting it into a sump.

Regarding the overflow and pipe dimensions does this seem correct to you guys ?

Pipe size..................Pump fed (l/h).............Gravity fed (l/h)
(20mm).............1500.........................200
(25mm)..............3000........................ .450
(32mm).................6500..................... ....1000
(50mm)............12000.......................2000
(63mm).................24000.................... ...4000

If you pump into the tank at 1000 liter an hour a gravity fed overflow system must be capable of draining at 1500 liters a hour.
so the minimum size pipe used for the overflow system would be 40mm to 50mm correct ?

 

I agree water changes is the only way to get rid of no3 in a non planted tank, i have not come across any other effective way as yet.
Seachem claims that matrix will reduce nitrate if used in the correct way, but i do not believe any sump/filter design will aid no3 levels.

Only the media you use, trickle system with DE-nitrate maybe.
If anyone has tips for reducing nitrate other then plants, water changes or chemical filtration please share the knowledge

 

What is the rate you want to filter? It must be the Monday blues, but why do you want to drain faster than you return? Since your control is on the return, I would rather drain slower than the pump capabilities. Also remember, the pump is rated at 1000lph at a certain height, if you have to return your water any higher than specified, it will slow down the water rate, and you do not want your tank to drain faster than your pump can return water....

 

Ran into a flaw/problem

To save on looks (didn't want big ugly white plumbing pipes in my tank) I built the first plumbing system on 20mm pipes, Black Garden hose.

The return pipe basically a "jet stream system" and the control junction is not working as well as hopped. to narrow the flow down to something the overflow can handle seems a bit tricky.
it seems to either lose pressure and not be able to take the water back to the tank (If the control valve is too open) or be spraying out both ends at a to fast a rate for the overflow pipes to cope.

Can I increase the flow rate of the overflow ?
If its working correctly and to full capacity what overflow rate should it be getting considering 20mm pipes ?

Thank you for helping with the development of this Chris & Esré

 

You could always add a second overflow, say on the other side of your tank, that will double your overflow. Your only other option for increasing overflow would be to attach a pump to it (defies the point of an overflow) or to use larger diameter piping.

What type of valve did you use? It sounds like you are using a quick-open valve, a linear valve might solve your problem. Maybe get one that you have to turn many turns to close for finer tuning in stead of one like a ball valve that closes with half a turn.

Re the overflow rates to expect, I have no idea, and in all honesty can't remember the equations used to calculate it, trying to look it up now. Are you measuring the 20mm on outer diameter or inner diameter? Water flow equations works on inner diameter

 

20mm inner diameter
What kind of flow do you get out of an overflow pipe with this many ebows ?
Its 5 x 90degree elbows and a T junction.

as a rough guess what would you say the overflow rate should be ?
I think you right about the valve though, have to go back to builders and get a more finer tuning one.

 

I can't say, best you can do is test is, or look online on engineeringtoolbox for the relevant equations, 6 sixpacks of red bull and a third year engineering student willing to work for food....

 

I would say you have way to many 90degree bends. I had the same problem with my marine tank a while back . With a 4500 lph pump and a head hight of a meter Ihad almost no flow . The same could be true for your overflow . I stand to be corrected but I remember reading somewhere that each 90 drops your flow by nearly a quarter . In the end I re did my entire return pipe with 45 degree bends and a more flexible piping .

 

Stormbringer and others,

You guys need to jack up your plumbing knowledge, the bends have nothing to do with it, it is the diameter of the pipe that plays the major role and 20 mm is just hopelessly too thin.

All of these questions have been discussed in previous threads on the forum, just go and look guys.

Kind regards,

Dirk

 

Will do prof and I agree 20mm to thin but to stir and already mixed cup , why then in my case did replacing 90deg bends with 45deg bends and less of them increase my flow .is adding many 90deg bends not the same principle as many compartments in a sump , each time water moves through the bend it is slowed down . So if I were to take 2 equally rated pumps lets say 2000lph In a 2000l drum each with 2m 20mm pipes one with 10 90deg bends or joints and the other straight would the straight ones flow not reach the end point faster and empty out first ? ,Or have I lost the plot here .

 

I think that your 90 degree bends were so tight that they were narrowing the diameter of the pipe. If you narrow the diameter you will obviously reduce flow but if you do not reduce the flow as most likely happened when you used the 45 bends then you did not reduce the flow.

When you are talking about free flow and opposed to flow when the water is pumped the flow characteristics change completely, because then the friction with the wall becomes a factor, as engineering principles would tell you. So for a overflow which is slow flow the diameter only plays a role, when you pump the water then additional factors come into the picture.

Engineering.....

Dirk

 

Thanks prof , spot on . Makes total sense .

 

I think my only option is going to be increasing the pipe size or looking for different joins.

I just bucket tested the overflow and wow its surprisingly slow about 70 liters a hour. can it actually be that slow or have i done something wrong ?

 

Hi Juddy,

Just forget about this DIY effort it has a far too narrow diameter. Go to 25 mm PVC minimum, you are wasting your time with this irrigation pipe stuff. Remember you do not want to overflow to be limiting, you want the pump to be limiting.

Kind regards,

Dirk

 

Hi @Juddy

I understand that you are wanting to use the black pipe because of colour. Pop over to Builder's Warehouse or an Irrigation Specialist and get yourself the 40 or 50mm irrigation pipe + fittings. That 20mm pipe is grossly limiting your flow, and completely defeats the purpose of the overflow design.

Regards

 

Thanks @Dirk Bellstedt and @Zoom

I am going to try find 30mm or 40mm. Limiting factor is that my Fluval canopy has precut sections for canister filter pipes which allow for a maximum of 40mm outside diameter pipe.

but even at 40mm what kind of flow rate can expected?
My Rough guess would be (Double the size of the pipe = half of the friction and double the amount of water)
70 liters now = 70 x 2 x 2 = 280 liters a hour.. really is that the best expected from a 40mm overflow pipe ?

Even if its a 1/4 of the friction it still only bumps it up to 400 odd liters.

 

Just remember, the area of a circle increases with a power of two, not linearly. So 20mm ID pipe as an area of 1256.6mm[SUP]2[/SUP], while 40mm ID as an area of 5026.5mm[SUP]2[/SUP] (2[SUP]2[/SUP] = 4 times as much). And while the area increases with a power of 2, the perimeter (where friction occurs) only increase linearly.

 

My maths was good... but not good enough to start talking about flowrates of different pipes. All I can say is that a 40mm pipe is NOT equal to 2 x 20mm. 40mm will be MUCH MUCH more. It's got to do with surface area etc etc.

Let me put it this way.... in concrete construction, steel reinforcement bars are used. (8mm, 10mm, 12mm, 16mm, 20mm, etc etc)

If the engineer SPECIFIES a 16mm bar is required, and I only have 10mm. Then I would have to use 3 x 10mm because it's got to do with the surface area of concrete attaching to the steel.

Look at all other big tanks... 40mm is more than enough for most tanks.

 

@Zoom Thats the thing Ashley, I see tanks of 500 liters odd running with 40mm pipes easily.. So I am assuming they are getting thousands of liters down that pipe in a hour.

Considering that I am only using this on a 100 liter tank with a 50 liter sump I thought I could easily halve the pipe sizes..
did i really reduce the flow rate 20 times just by halving the pipe size.. or is there something wrong with the actual construction of the overflow pipe..

 

By halving the size of the pipe, you are not halving the flowrate. Your are reducing the flow rate exponentially.

You could even go with a 32mm.

But you also need to remember something here... your pipe will only overflow the volume of water that you have pumped into the tank... hence this is called an OVERFLOW system. No point in aiming for an overflow system that can take 1000l/h when you are pumping water back up at 750l/h.