Hello! I'm new to this forum and relatively new to reef keeping... My husband and I have had saltwater tanks (dead coral and fish) since 1990 or so. Converted our 65 gallon tank to fish and live rock last year, bought new lights, switched to live sand, and have been adding live corals since August 2000. We have had a great time with Soft and LPS corals, and are now getting into SPS and clams —Â*which leads me to my problem...
We purchased a 2.5" purple Maxima about four months ago. It has attached itself to a rock about 8" from the surface. This clam has never fully opened up. It opens, but never fully extends it's mantle. It doesn't seem to be "gaping" and definitely reacts when the fish swim over it. It is not in a direct current, and there is no sign of snails or bullying by the fish. It seems to be holding it's own — just doesn't compare to the photos I have seen on this forum. We figured maybe it was just a "bad" clam...
Last Saturday, we bought a 4" purple Crocea. This one was fully open in the store, mantle nicely extended. Looked great Sunday, but by Monday was starting to look like the Maxima. Same for today. I did notice, however, that the mantle seemed to be out more this morning when the Metal Halide was off. When I went to check on it at lunch (Metal Halide on), it was barely open. She (Clarice) is located about halfway up and seems to have attached herself to a rock.
The water quality seems to be in the ranges I have read about (all of the corals look great...) Here are the test results from yesterday:
Phosphates: 0.3
Nitrates: 0
pH: 8.1
Ammonia: 0
Nitrites: 0
Alkalinity: 5.6 dKH (adding C-Balance to get this up)
Calcium: 450
80°
1.023-1.024
I have been searching for answers all morning and am starting to wonder about the light. Found a cool site — On The Half Shell, By Daniel Knop. In his article, "Tridacna crocea — Pearls of the Reef," he says the following:
"Because this clam receives the full spectral composition of the sunlight in nature, I prefer metal halide lamps with Kelvin (K) values between 5000 and 6000. Lamps with higher K values (10,000 to 20,000) that produce more blue spectrum mimic the natural illumination on the reef to a greater depth (e.g., 10 or 15 meters [30 to 50 feet]). This may be ideal for coral species naturally found in this habitat under these light conditions, but it is not sufficient to provide the clams with everything they need."
Our setup consists of the following:
4 – Icecap 660 VHO / 380 watts / 2 Actinic, 2 AquaSun (since 2/00)
1 – 250w IceCap Metal Halide / 12,000K Sunburst (since 11/00)
Could this be the problem? Is anyone else using the 12,000K Sunburst?
Any comments and suggestions will be greatly appreciated! We really want Clarice to make it!
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