Maxi blue clam sucks a lot of cal ?

[Jakef150]

I noticed my cal dropped from 440 to 360 in 3 days..
Alk is 9.5
Do maxiam sucks a lot of cal ?

It's 3"

Thanks
Jake

[NoahP]

Yes clams use a lot of calcium.

[moliken]

there is some other reason for that depletion. one clam cannot reduce ca that much in that short a time. maybe in a 5 gallon tank, but not in something greater than a 20. how big is the system? what else is in there? what kinda kit? last water change? slowly increase ca w/ some ca supplement and decent w/changes. use a chemistry calculator to determine how much additive you need
http://reef.diesyst.com/flashcalc/flashcalc.html