I have been researching all the cuttle articles I can find (TONMO, the ceph page, goggle) and can't find anyone recommending calcium.

I was thinking how does the cuttlebone grow without calcium added? I understand why octos wouldn't need it, but that cuttlebone has to grow awfully large-awfully fast. Could that be a limiting factor in the raising and breeding of cuttlefish?

I noticed in some of Colin's photos he had corals, did they receive additives? I also noticed that the brand name "Fuji Mud" is talking about the calcium and minerals in mud patched just outside the reef systems.
http://www.marinedepot.com/md_viewItem.asp?idproduct=WS1111
http://www.marinedepot.com/aquarium_additives_walt_smith_fiji_mud_g old.asp?CartId=
This is also where cephs like cuttles and muck animals mostly live. Could they need these conditions to thrive?

Unless anyone can give me a reason not to do this, I am going to try supplementing my tank as if I was stocked with stony coral. I will be learning how to track absorption of calcium, so I can see if it is actually being used.

Depending on what type of salt mixture you use, it contains calcium. Check out this site for information on major brands.
http://www.aquacraft.net/issue3.html

Not touting any brand, so I won't mention it. I get quite the coraline growth, it works great for me.

I just noticed the presence of copper in Instant Ocean brand from the link above. What is the lethal amount supposed to be?

I think it's supposed to be small enough that the water test kits cannot detect even a trace of it. Not sure about the exact amount though...


Speaking of Calcium, I've also seen a friend of mine use it as a PH buffer or something...not sure is it good for the coral and fishies though (not cephs, he says he'd rather eat them than keep them.)