Crumbling LR = low Ca+???

[MedcinMn]

A friend was over and while fragging some corals, pieces of my LR were kind of "crumbly". Not just the coralline algae, but the rock itself.

He heard low Ca will cause this. My Ca is around 400.

Anyone else ever hear this?

[lvpd186]

I've never heard that but you should probably test your ph. Besides I wouldn't really call 400 low.