Help requested on lighting please

Ok, I have been to Builders today looking for some fluorescent bulbs as I currently have 2 that came with my tank when I have purchased it (4 ft Sun Sun curved - do know about the danger of bursting - only discovered it after buying it last year May). There are no printing or markings on it indicating the wattage or K rating leaving me a bit in the dark:hmmmm:.

I recently started off with a planted setup and want to insert 6500k bulbs (daylight). The ones I saw at Builders are 30W 4000K and 30W 2100lm. the question is as follows: How do I convert lm to K? What will the K rating be on a 2100lm and what will the lm rating be for a 6500K tube?

Do have Dwarf Bacopa (Bacopa monnieri), Java fern (Microsorium pteropus), Amazon sword plant (Echinodorus amazonicus), Hair grass (Eleocharis acicularis). I dose with Seachem Flourish comprehensive and Seachem Potassium. Do have Seachem Excel but do not use it because of the Java fern.

Substrate at this stage is normal silica but going to change to PFP capped with pool filter sand during long weekend and insert the Seachem flourish root tabs when substrate have been changed. Any other suggestions??

 

Lm and kelvin are not same thing. One is basically how bright the globe is, and one is the temperature colour. So as far as i know you cant convert them.

A 6500k with 2000lm will be brighter, or more poweful rather, than the same 6500k tube with only 1800lm. But both will have a daylight colour to them.

 

A simple example is the phillips make 2 cfl globes that are rated at daylight (6500k). One is called a genie and one is called a tornado. The only difference is the lm on the tornado is higher. So basically they have the same wattage, the same kelvin. So they use the same amount of electricity, they both visually look the same in colour (daylight) but the tornado penetrates the water better because the lm is higher.

If my physics is correct, one lumen is equal to one candle. So 2000 candles wil just be brighter than 1800 candles. The colour of the light from the candles is the same, its just that 2000 candles will light up a slightly bigger area... or in our situation, penetrate the water more... more light will reach the bottom of the tank.

 

It's true what Zoom is saying. If a tube does not indicate a K value you can assume 4000K. Not very accurate I know, but since 6500-10000K is more expensive the companies is more likely to mention it.

I have had a very successful planted setup with 4000K tubes, and a couple of the guys on another forum mostly use 4000K, but rather try to get Daylight with high lm value (keep budget in mind lol)

 

This is always a interesting thread to read:

http://www.apsa.co.za/board/index.php?topic=4454.30

 

Thanks guys, it shed some light on my prediciment, lol:wink: