That is a LOT of light for not having CO2, you are asking for algae IMO. T-5's are an excellent choice though. Cheaper than PC's, but with a bit of extra light since they have less "re-strike" than do PC bulbs. I also have a 125 but I have 4 x 96 watt PC's and the tank is CO2 injected, I still get some algae. If I had it to do again I would just buy 2 shop lights with electronic ballasts and run T-8's in them which can run you as little as $32 total. Of course you would probably want a cap on top of the tank to hide the lights then.