My only thought is if you're doing CFLs, might as well bump it up to 32 or even 42 watts, unless that's too bright for you. I'm using two 2700K 42w CFLs in my 20 gal long setup, but it's not really "low light" so maybe it would be overkill for you. Most plants (even low light) won't complain about a little more light, IMO. But I'm relatively new to the planted tank hobby, so my advice should be taken with a grain of salt.
Last edited by winn; 01-11-2016 at 06:36 PM.