CFLs that use 20 watt but put out the equivalent of 70?
I'm setting up my DIY light system for my 20 gallon and I'm freaking out because I'm having a hard time finding the proper CFLs for it... I went to the hardware store the other day and the guy there showed me a bulb that uses 20 watt but puts out energy equivalent to 70... Do these kind of bulbs 'exist' or is he just trying to make money? Either way am I safe to put two of these on top of my 20 gallon or will I get TOO much light if they put out 70 watt of light? I'm dosing CO2.
Oh and my main concern, will I be able to grow any kind of plant with two of these bulbs, even if they don't really put out 70 watt of lights? This is killing me, I really want to set up a high light planted tank but I can't find any strong lights, the 50-60 watt ones are huge...