All 24" normal flourescents are going to be around ~17-20W and power glo lights are labeled 18,000K but thats just a 'marketing creation' for the most part you can ignore the K rating of Hagen lights they are mostly made up numbers. Personally I'd never use all the same bulbs, variety is the spice of life (literally) and I would suspect that power-glo's dont have much red in their spectrum.