HELP! Bad spot on my clam - getting bigger

[stang8s]

Any help on this would be appreciated. I have had this deresa in my tank for about 3 months now. A few days ago I noticed a small spot on it, and today i notice it is much larger. Please see this thread for photos and more details. Thanks!

http://216.235.242.50/forums/showthread.php?p=62998#post62998

 

[Peabody]

Could eb central bleaching. What lights is he under, what spectrum, how long since bulbs changed?

Please also list chemistry in detail and how it is measured.

Hope we can help!

 

[stang8s]

It is in a 75gallon the lights are two 175w 10k and two 110 actinic vho. The actinics are due for a change im guessing but the halides are about 8 months old.

I have not tested the water thoroughly yet. I just now checked salinity with my refractometer at 1.024 which is typical for my system. The ph on my meter is reading a bit high at 8.7

I will do some other tests but I doubt anything is off, calc reactor keeps alk/calc dead on and all corals looks great with full polyps
thanks
Jeff

 

[Peabody]

Hmm..I would suspect off SG or ALK if anything, but those seem fine. WHen have you last tested CA/ALK? Recently?

 

[stang8s]

Just tested tonight. Both were a hair on the low side for my tank, but nothing to cause issues in my opinion. Calcium 400, Alk 2.5

If i bump the bubble count on my reactor slightly it should raise both of those and lower my ph a bit in the process.

I notice the cleaner shrimp on the clam again tonight. I would think if it was harming it, it would close up tighter and not let it...