Corals turning brown

[Fizzerman]

I have a 40g frag tank. I run one 250 watt 14k Hamilton. The bulb is only three months old. I had a green slimer turn brown and some other corals turning brown. Is it because of the light or something else?

[Sk8r]

How deep are they? Height of light? It could be the light. Check alkalinity: that can be a problem.

[Fizzerman]

Lights are 10" above water the corals are 6" to 8" under water.

[Sk8r]

Try lowering them to about 10" or raising light 2". I run a 250w in not too dust-free water at about 10" (counting thickenss of fixture) and have most sps corals at around 8-10, one torch at 6. Everybody's happy, but my water clarity is not the highest.

[downhillbiker]

are the corals new? did you aclimmate them to the lights. they may be going through light shock. this is common if you bought them from someone with lesser lighting such as VHO, t-5, or old metal halide bulbs. i also recommend lowering them in the tank.

[Fizzerman]

alkalinity is 10dkh. The corals i had them for about a month and the person i got them from had 20k Radium 400watts.

[Anemonebuff]

Excess nutrients can cause corals to brown.

[Tang Salad]

Yeah too much light shouldn't cause browning, but high PO4 and NO3 certainly will. In fact you can ignore your test results; if the SPS are getting browner, then you have those nutrients and should work to remove them.

[downhillbiker]

<a href=showthread.php?s=&postid=13074956#post13074956 target=_blank>Originally posted</a> by Tang Salad
Yeah too much light shouldn't cause browning, but high PO4 and NO3 certainly will. In fact you can ignore your test results; if the SPS are getting browner, then you have those nutrients and should work to remove them.

i originally heard too much light doesnt cause browning too, but mine went through browning, then bleaching, then RTN. light shock was certainly a possibility, but since light PAR is probably close between the two lights, this isn't a factor.

i would say that testing needs to be done, and the skimmer needs to be checked. maybe crank it up slightly. PO4 often doesnt show up on test kits, but is still there, it is just being used up by algae as it is produced. do you have algae issues?