Originally Posted by mr_X
I would say that high output T5's are every bit as good as metal halides, and penetrate just as well.
To answer your question I must first as if you have photosynthetic creatures in the tank. If you have corals/clams/anemones, I would suggest you run all lamps at least 8 hours. they should be on a timer so that there is a definite night time period as well. You should run the night lights (if you want to) an hour before and an hour after all lamps are lit, just to give the tank a morning/evening transition. This is personal preference though, because this transition does nothing to benefit photosynthetic creatures.
bottom line- all lights on for at least 8 hours, and all lights off at some point during the night.
There is nothing in the tank yet.
I just purchased the skimmer last weekend ,
And wanted lights and skimmer before adding anything .
All parameters are good .
It has been over a month since it has cycled .
Back to the lights .
Total darkness is ok ?
I read something to the affect saying total darkness isn't good cause in nature the moon lights the water .
Unless you are deeper there will never be total darkness