can light kill coral ?

[laurentb]

i switch to metal halide last month and i lost 3 lps corals. can that be the light ? on a 75 g tank i put 1 MH 250 W 10K hamilton. i lost a pepperment shrip today.
ph = 8.3
alk = 9
Cal = 420
nitrate = 0
phosphate = 0
temp= 80 F
i feed them with phytoplanton 2/week.
light 9 hours a day

 

[PUGroyale]

I imagine the shrimp was incidental. I'm not a big LPS guy but I do have an acan, I have to keep it under a plate montipora in the shade or it starts losing flesh on the raised skeletal areas. hth

 

[Freed]

If it was quite a bit more intense than what they were used to then yes. If you didn't back off your photo period and subjected them to the full 9 hours of MH when they were used to PC, VHO it could have done them in. MH is much more intense than the others so you must at least shield the corals from the full effects of the MH with layers of window screen or a shorter photo period for a while and then increase the photo period or remove layers of the screen over a couple weeks time.

 

[r00onmac]

definitely killed 7 heads of my torch with my MH by lowering it too quickly and not realizing what it was that was killing them... now i have a measly 3 headed torch with way more skeleton than flesh... i just keep hoping those 3 will split soon so it can go back to its glory days...

in short,,, yes

 

[atvdave]

I'd like to sneak in on this post also.

I switched from MH to T-5's about 1 month ago. The first 2 week the tank looked great, but now the last 2 weeks my hammer, toadstool, frogspawn, and 2 green polyps just wont open up as much.

My MH was 2x175w and my T-5s are 14x39w (7 rows each side) on a 72x18x21 tank

My Zoa looks great and spreading and my water test good also.