Metal halide sunburn?

[xroads]

Can you leave your MH on too long. I bought some corals on Sat and they looked great all day yesterday. My new leather was plump with all the little polyps out all over it. I bumped up my MH to come on @ 11:30 instead of 1:30. Tonight about 7 I noticed that the leather seemed to be shrinking before my eyes with no polyps out and kinda turning white. I turned everything off but the antinics and it seemed to help plump it back up. Everything else was looking good any way.

Help please
Craig

 

[gobyfann]

I don't know about 'sunburn', but changes in lighting are a cause of bleaching/stress for corals. When we upgraded our lighting to metal halides we suspended varying sizes of plastic mesh sheeting just under the water on the whole tank. The first layer was a suspended ceiling light panel cut to size and then we put layers of plastic 'crafting' mesh on top of that. (from hobby lobby). Every day or so we'd remove a layer of plastic and after a few weeks we got rid of it all. We still had a few mushrooms stress on us, but moving them to shady areas of the tank brought them right back. Wetwebmedia.com has lots of great information about acclimating stuff to lighting, etc.

 

[jonesey_89_]

I know i got a sunburn from mine once...

 

[sipe]

Craig,
Most reputable coral dealers would tell you to decrease the photoperiod when you add new coral for a few days to allow them time to acclimate to your water and then soak up the rays. The increase from 150watt MH in my tank to 250watt Mh in your tank would definitely strain the coral.

Decrease the photoperiod for a few days and then then gradually increase it.

Chris

 

[cabenn]

There's a trick to acclimiating your corals to the new light. It involves using nylon screening and removing a layer of screen like very few days.

But yes lowering your photo period down to about 1/2 the time will also help. I'd let your coral regen for at least week before turning on those halides again.

Yes I too have joined the MH sunburn club. It hurts

gobyfans plan seems to be pretty similar to the one I've read about. Egg crate and nylon screening.