What kind of fish actually like bright light? I just watched an old video of one of my tanks and I realized that over the months my ludwegia has been getting smaller and smaller and I am thinking of making a brightly lit tank to grow it back out again.
I dont really think you need "bright light". What size is the tank you are talking about and what are you currently using for lighting. A lot of useful info can be found in the Planted Aquarium forums.
I am using a pair of 20W CFLs in my 15g tank and my plants and fish seem to be just fine. I am putting out approximately 10WPG(watts per gallon) Its been recommended that you have at least 2wpg for most plants I guess. I am not an expert, but I bathe my plants in a pair of 6500k (light brightness) for 6-8 hours a day. I expect a bit of algea growth and have taken steps to deal with that too.
the 10WPG is because the CFL's I have are rated at 75w, so...
Actually, it doesn't work that way. The WPG rule is for flourescents not incandescent equivalents. So if you have 40W over a 15gallon tank you have 2.7 WPG... a decent amount of light for growing many plants... I use 2.4WPG.
Actually, it doesn't work that way. The WPG rule is for flourescents not incandescent equivalents. So if you have 40W over a 15gallon tank you have 2.7 WPG...
Yup...75w equivalent applies to standard incandescent light bulbs. 75w of incandescent light does not = 75w of standard NO fluorescent lighting.
So, I agree...the wpg rule does NOT apply to CFL equivalents.
Wycco and Slappy are correct, the WPG equivalency doesn't apply...watts are a measure of power usage so basically what they are saying is that the CFL is putting out the same amount of light as a 75w incandescent at a lower power usage, ie. they are more efficient.
Anyways I wouldn't worry too much about how bright the light is...I used a couple 15w CFLs on my 10 gallon and it worked fine with most plants.
