Just curious about how many watts per gallon, brand, led, flourescent, need for co2 system. I have a 15 g tank with standard single 15watt bulb. Plants seem to be growing fine at this point, but I was told I need to upgrade my lighting and possibly get into a co2 system to grow plants of lighter color and most ground covers. Can anyone help me figure out a cost effective system to help my tank along and not get too much algae? Ive heard of a yeast co2 system too, whats up with that?