Need more or less light?

[wharfrat48]

How can you tell a clam is getting enough or too much light? I have a derasa on the sand which has been doing great and growing for about 8 months. I got a maxima about a month ago and I can't tell if he's happy or not. Seems to be extending and reacting fine, but I'm starting to notice spots on the mantle that look like "thinning" areas. Not holes, but maybe areas where the "skin" is fading. Can't explain it very well. Anyway, what do you think?

Rich

 

[tomterreefic]

The Maxima generally require more intense light than a Derasa. Is it in the 75 under the T5 lights? If so, where is it located on the reef, sand bed or up the rockface? I don't know that T5's will give enough PAR, since the intesity is diffused over the length of the bulb. If your clam is low, then maybe you could move it up on the rockwork. I'm sure some of the longtime clammers will chime in with some helpful advice.