How long should I leave my MH on for?

[RedDragon]

I have been reading a little about the time's some members have there MH's on, well is it bad to have the on most of hte day my MH go on about 9 and off for about 1 hour at 3 and that on till about 7 for an hour is it bad to have it on almost all day or for a long time :roll:

[reefer]

imo, you should try to simulate a normal photoperiod. in the natural enviroment they normally receive 10-15 hours depending on the location of usable light. you could be inducing unneeded stress to your livestock and corals, imo.

quote from my reef guide:
"consider making an effort not to startle your fish with the sudden switching of lights. in nature the sun doesn't drop like a rock, so neither should the ones in your aquarium, you can mimic a more natural sunset and sunrise in a couple of different ways, but that requires more than one light source. "
"just remember that some animals are diurnal and some are nocturnal, so you really need to simulate day and night in your aquarium."
hth!
:shock:

[Tim Marvin]

I run my halide 8 hours a day, and the PC's and VHO for 12 hours. The halides run in the middle of the day to simulate mid day sun and the other lights do the sunrise and sunset effect.