Too much LED lighting ? Help needed

[tubamanandy]

Currently using 2 X 36W LED spots 6700K on net 90 litre tank (72x35x50 cm) - full CO2/good substrate/decent circulation/EI dosing/50% water changes weekly.

I'm starting to think I have way too much light and maybe better with 2 x 21W spots as algae is becoming an issue.

Would really appreciate your thoughts on my led lighting levels.

 

[tubamanandy]

Forgot to say, dropped photoperiod recently from 7 hrs to 6 hrs to try to help. LED spots are suspended around 10" above the tank

 

[Martin in Holland]

I don't know way we are still so fixed on Watt.... if I use an old light bulb of 100W that would be a lot less than a T5 100w light... shouldn't we measure with Lumen (Lux)?...you would need 35 to 50 Lumen per liter for a planted Tank (some plants closer to 50 and others closer to 35)...this way no matter which kind of light we use, it should always be good. Of course you still need to look at the light color or Kelvin. Which I think most of use will use 6500 and maybe at midday 10 000K.

 

[Yo-han]

I think it is verg hard to tell without measuring PAR, but I can tell I used 2x27W (I believe, TMC grobeam tiles) on a 250L. All plants grow fine, no need to go higher IME. But get yourself a PAR meter to find out for sure, WPG is useless.

 

[tubamanandy]

So what I have appears massive in comparison - would you agree ?

 

[Martin in Holland]

So what I have appears massive in comparison - would you agree ?

it's impossible to tell without knowing more about which LED lights you are using....so many different kinds on the market....

get yourself a PAR meter to find out for sure

I agree...best way to know which light you have and if it's enough (or not) is by using a PAR meter...maybe you can borrow one from a friend or photographer

 

[sciencefiction]

Not sure what LEDs you are using, but if they are like mine(made of 3W high power Crees) then 2x36W LEDs roughtly equal 96W T5 HO, which is way too much over a 90L tank, something like 4W per gallon.