Calcium in aquarium wood

[Simmo]

Hi Folks
Bit of an odd one this, I read that wood contains calcium, the oak chunks in my tank are friable on the surface and my new shrimp are feeding on this surface. Is the calcium available in a form that is available to shrimp and snails? My water is very soft but maybe there is no need to increase hardness or provide cuttle bone etc if there is a whopping big calcium source already there? The bladder snails have been there since the start and shells are not deformed.
Thanks!😀
Dave

 

[dw1305]

Hi all,

I read that wood contains calcium,

It does. You could liberate all the metal ions in the wood by burning out the carbon and collecting the ash, in which case the ash is about 25% calcium (Ca), but you don't get much wood ash <"from a lot of wood">, for Oak I think it is about 0.5% ash, so the wood is ~ 0.13% calcium.

Is the calcium available in a form that is available to shrimp and snails?

Not really. It is bound in <"with the lignins"> etc. which are very resistant to biological degradation.

My water is very soft but maybe there is no need to increase hardness or provide cuttle bone etc if there is a whopping big calcium source already there?

Cuttle "bone" is 100% aragonite calcium carbonate (CaCO3). The RAM of Ca = 40 and the RMM of CaCO3 is 40 + 12 +(3 * 16) = 100, so Cuttle "bone" is 40% calcium and that calcium is a lot more accessible than in the wood.

Leafy green vegetables are another good calcium source, but even that is relative. Brassicas (Kale, Cabbage etc) only have about 0.25% Ca, but that is much more available than in the wood

cheers Darrel

 

[Simmo]

Hi Darrel,
Thanks, thats really interesting, appreciate the knowledgeable analysis 👍
Cheers
Dave

 

[dw1305]

Hi all,

appreciate the knowledgeable analysis

Alas, not everybody does.

cheers Darrel