light cycle

Especially when you consider how many of us have mixed reefs with stock from all over the world.

Exactly. The point is to do the best you can for your inhabitants. That means don't have 16 hrs of light but don't have just 5 either. You have to find a happy medium.
 
Only using MHs I don't dare leave them on 12 hours.

I would agree with that statement. As well as I don't have your convenience.. I am away from my home for at least 8 hours a day and want to enjoy my fish for some of the time when I am home.
 
I would agree with that statement. As well as I don't have your convenience.. I am away from my home for at least 8 hours a day and want to enjoy my fish for some of the time when I am home.

Same here but I work 10 hr days so I want to see them for atleast an hour.
 
I have my mh come on at 3 pm and off at 11 pm. I do it that way to fit my schedule. There is no sense in having the lights on when I'm not around to enjoy my tank.

I agree. Why have the tank lit when you are not home to enjoy. I have an 8 hour day 2pm - 1opm. It's a bummer on the weekend but this is when we do maintenance on the tanks.
 
Why is it bad to have have light on for 16 hours? What are the benifits and what are the concerns (besides money)? Can a fish have too much light?
 
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