diatom Algae

[garyko25]

Started getting a lot of diatom build up. I put three smaller pcs of rock in the tank. I wondering if the halides are staying on to long. Can anyone let me know a good amount of the throughout the day halides should stay on for. It's a 90 gallon reef with 2 250 watt hqi's and 4 pc's. Soft corlas and zoa's and fish. Thanks

[tony]

i keep mine on for 8 hours (250w hqi over a 30 cube)