Aragonite in axolotl tank for raising pH?

[aoeu]

I recently got an axolotl. I use very fine white sand in my tank, and I've noticed the pH of the water decrease slowly over time - so that it's about (or under) 6.5 at this point. I'd like it to increase to a more suitable level for axolotls, and I've read all over the place that crushed coral is the way to go when attempting to raise pH.

So I bought a giant bag of crushed coral on amazon, but now I'm realizing it has the term "aragonite" written all over it. After a bit of research, I've found that aragonite supposedly isn't safe for axolotls.

I've filled a small filter media bag with the stuff and placed it directly in the aquarium. Is aragonite safe when used in small amounts like this? I assume that using aragonite as the primary substrate could be unhealthy, but I'm not sure about my small bag.

 

[JM29]

Hi,

Aragonite is the usual forms of Calcium Carbonate biosynthetized by corals and molluscs (snails, shellfish...). I don't think aragonite in itself is unsafe for axolotls. But the size and shape (rounded or sharp) of the pieces of coral seems more important.

 

[aoeu]

Those were my initial thoughts... I've put the aragonite in a filter bag so I don't think my axolotl will have any issues regarding safety. Thanks for the input.