I have two tanks with crypts that receive identical treatment as far as CO2 and EI are concerned. The tank with Flourite has far superior growth in it over the other tank with Onyx. I know Onyx is supposed to have a "slight buffering" capacity and I'm wondering if that is the difference. I'm considering getting rid of the Onyx and getting Flourite for that tank, but it's an expensive proposition.

thanks for any comments, observations, etc.

-Russ

Hard to say, adding some mulm and peat to flourite likely will help.
Onyx is great for a few species of Crypts though, not so good for many others.

Regards,
Tom Barr