Originally Posted by James From Cali
The CO2 in his 55g had broken the marble down. He has no CO2 in the 10g but he has the marble. In the 55g he has CO2 and a dissolving piece of marble.
Doh! Reading that post too fast.
Thanks for pointing out my dullness.
I don't really think the rock would have upset your 55. In the 10, the volume of water relative to the rock might have been a problem if you were injecting CO2, but in the 55, shouldn't have been that drastic. Did you seen significant rises in GH, KH and pH?