Done trying clams

[chuckfu5]

I don't think your clam died cause not enough light in a week, clam died cause of weak light after a month or two but if you getting a unhealthy clam or something bothering it like diseases, pest, parasite, bacterial infection or something nipped at it then it goes down hill very fast.

I don’t either but I’m being told from several people my light can’t support one. I’m trying to rule that out.

 

[DSC reef]

Your light can support it, it's finding the balance that's hard. Plus there's to many variables for someone to say it wasn't your light. No one knows the condition of the clam before you got it, could have parasites, you never know. Truth is keeping a clam in that tank is going to be a challenge regardless. I've kept many clams over the years with my oldest over 5 and I've lost clams unexpectedly too. These are sensitive animals to keep no matter your skill level. If the clam has been kept at a par of 250 for a period of time then it goes to your tank and that gets cut down to say 85 par then that's an issue especially if the clam is having other issues or stressed. A 4 hour acclimation can add to that stress. So many variables, no one can say why it died, were just trying to help with the experiences we've gone through. If you try another clam I'd still suggest a deresa once your tank is stable and the lighting is figured out. If your ramping up the light then you have to give the other corals a chance to acclimate too. Also, plenty of people have kept divers den clams successfully including me. I've lost ORA clams too and they have a great reputation not including that a lot of vendors get there clams from ORA.

 

[IronChefItaly]

I don’t either but I’m being told from several people my light can’t support one. I’m trying to rule that out.

Assuming 12 inches of water and 4 inches of air, I would approximate your unit's intensity at 100% to be 160 PAR in ideal conditions (zero turbidity/max performance). (source - 4:35, youtube.com/watch?v=wavz8K63-Oc)
"So, the deepest living tridacnid has never been found where intensity is lower than about 150 µE/m2/s, and all the rest live in waters where the intensity is higher." (source - http://www.advancedaquarist.com/2011/3/inverts)
"T. maxima specimens can do just fine when maintained under much less light (200-300 µmol·m²·sec, or 10,000-15,000 lux, is generally sufficient)" (http://www.advancedaquarist.com/2008/1/aafeature3)

Other great resources...
http://www.denix.osd.mil/denix/crid/Coral_Reef_Iniative_Database/Red_Sea_Region_files/Jantzen et al., 2008.pdf
https://www.nano-reef.com/forums/topic/319637-tridacna-lighting-and-nutrition-requirements/
https://www.petcha.com/lighting-tridacna-clams/
http://animal-world.com/Aquarium-Coral-Reefs/Care-of-Tridacnid-Clams

I cherry picked some information to help you arrive to your own conclusion. My understanding, is at 100% intensity your light is "likely" inadequate for keeping a maxima positioned on the sand bed. Three recommendations are as follows...
1) Select a clam specimen that has been proven to be sustainable in lighting intensity similar to your own
2) Select a less demanding species of clam (as others have mentioned)
3) Position the maxima clam closer to the light source as to receive 200 PAR at a minimum (take special care to acclimate to this intensity, it may also be worth mentioning that maxima clams are NOT sand dwelling and prefer a rock surface to attach to)

To me, it is simply not enough to say "myself or others keep this species of clam in such conditions so these conditions will work for your clam". If you skim through the links provided it should be readily clear why this generalization cannot be made.

 

[DanConnor]

There appears to be a problem with Perkinsus infections lately- possibly spreading at wholesalers. Don't buy another unless the seller will quarantine it for a month...