I've been thinking that my 25 gal. tank just hasn't looked as good as it did when I first got it. I figured that it was because it is well established and I've had it going for years. By and by I read something around here that says flourescent tubes are only good for a year or so (or a number of hours). So I decided to try a new tube and OMG! I can hardly believe my eyes! The tank looks really good again and the fish look great! I can SEE everything so much better. I had no idea how much a flourescent tube degrades over time. I figured you just change the thing when it won't light up any more. I've had that old tube for years. :thud: