Welshy
Aquarium Advice Freak
Hi I gave just been looking for 20w t8 tubes and can't seem to find any that are not by hagen glo, I have read somewhere that fluorescent tubes wattage go up in size, now what this guys saying that a 24" tube is an 18w tube and not a 20 he argues it's just a gimmick, my question is is this true? Can I put a 18w tube in my 20w ballast ?