Treatment Advice Needed on Sick Maxima Clam

John Helm · Jan 14, 2014

Greetings to all R2R forum members. This is my first post. I had posted this same question on Reef Central and haven't received much help, so I thought I'd try here, especially after reading such great information on tridacnids on this forum. Last March at the CT frag swap I purchased a small aquacultured maxima clam from Pacific East. I had him in an IM Nuvo 16 for about a month with the stock lighting and he did very well. So I transferred him to my 90 gal mixed reef and placed him on the sand bed. The clam did well for months and showed decent growth. Within the past month, he's been exhibiting what I think is PMD, but since I have no real experience with clams, I'm not sure. He seems to be open completely but the mantle doesn't extend. Also, the edges of the mantle are curled and white in certain areas. It's a bit difficult to see from the photos. I had been running GFO and carbon with 2 BRS reactors to help eliminate GHA and to keep the water clear. This worked and showed no effect on the clam. I stopped both of these several months ago, but just began to run the carbon again recently in an attempt to help the clam. I'd say there's been some minute improvement but not really significant. There are no pyramid snails that I can see. (I checked after lights out all over the shell with a jeweler's loupe). My lights are two Ecotech Radion LEDs (1st gen) which ramp up to about 90% intensity at their peak. Total light time during the day is about 12 hours with moonlight towards the end. The clam was on a rock about 4 inches up from the sand bed and about 23 inches from the light. Here is a photo of the clam when I got him, and one from about two weeks ago. I did a fresh water dip for 25 minutes and the final photo was taken a day after the dip. I also moved him back to the IM Nuvo 16 under a Kessil A150W and the stock LED's. I did this just in case any fish or other creatures from my DT were harassing him. He seemed somewhat better after the dip but continues to show the same symptoms, but remains very reactive. In the final photo you can more clearly see the curled and bleached edges of the mantle. Has anyone had experience with these same symptoms and effectively treated them? Any help is greatly appreciated.

Here are some parameters from my DT:
90 gallon DT
20 gallon sump
Reef Octopus Extreme 160 skimmer
Eheim 1262 return
4 Koralia Evo 1400 circulation pumps
2 Ecotech Radions 1st generation
Temp: 78
pH: 8.2 - 8.3 depending on time of day
Salinity 1.026
Ca: 440
dKH: 7.6
Mg: 1400
Nitrates: 0
Phosphates: 0.02 (Hanna P04 checker)
Tunze ATO with RODI showing 0 TDS.
I do have some red cyanobacteria on the rocks. No GFO being run currently.
I also dose a 3cc mixture of vinegar, vodka and sugar daily.
Since moving the clam to the Nano, I removed all vermitid snails from the shell in case they were an irritation.