Light time limit

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Aquarium Advice Activist
May 18, 2009
i've noticed that when i turn off my light that all my corals shrink quite a bit and grow back to normal size after having light on for a couple of hours, is it bad if i leave my light no all 24 hours or is its normal for corals to shrink?

i have a pc with 1 blue light and 1 white light and then have a 2ft bar of consisting of 30 led's as a moon light
Not so wierd.....Corals are animals and as such need a rest period of at least 8hrs. It is normal for them to shrink up after the lights are turned off.
More important then the type of lights you have are the Wattage of the lamps.
Corals will always close up a bit when the lights go out.... just like thincat said, they need a lights out period for at least 8 hours but if you run those light for more than 10 hours you risk an ugly algae outbreak. Run for ten hours or so then turn them off in my opinion.
typically have them on for 10 hours so i guess im good then...thanks for the quick replies
Think of it as nature.....there is not sunlight 24 hours a day. 8-10 maybe even 12 hours a day is good.
Your lights should be good for most low light corals, LPS types.
i have a couple mushrooms, torch coral, anemone, and a couple corals i think are referred to as candy canes or sun corals...

is my light sufficient for these, if not what wattage do you recommend?
Okay, long has your tank being set up? You don't have enough lights for the anemone! It needs at least 200 watts of either T-5 or MH lights. You are looking for intensity and penetration which the PC lights lack. If the coral you are talking about is a sun coral it does not need much if any lights, but you have to feed each polyp.
wouldn't 200 watts be a little intense, i only have a 55 gallon tank?

the lights i have now seem to bring lots of life to my corals as they have grown much larger in a matter of 1-2 days...
Nope - not too intense at all. I have 200W of power compact fluorescent over my 46 and I'm at the low end of lighting in my book. (And I still consider myself with too little lighting for an anemone, by the way.)
well my white and blue light have 2 bulbs each, does that mean that each bulb is 65 watts or is it that combined wattage between both bulbs.

if thats the wattage for each bulb than 4 x 65 = 260w so i guess i should be fine
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