Aquarium Crystals

[ButterstheAngel]

Does anyone know which types of crystals are safe for freshwater tanks? Here’s a photo of the ones I have. I did a nitrate drop test and none reacted. Should I boil them? Thank you!

 

[Aiken Drum]

Some crystals are safe, others arent. There is a list of whats safe and whats not here, but specifically what your crystals are, i dont know.

https://www.google.co.uk/amp/s/forg...-wanna-add-some-crystals-to-your-aquarium/amp

Personally i wouldn't risk it unless you 100% know what your crystals are.

Never boil rock. They can explode which is dangerous. Its safer to pour boiling water over rocks but there is still a risk.