Crushed coral for substrate?

[aydemir]

My SO parents started a FOWLR and opted for crushed coral as a substrate. I would've recommended sand if I had known they were starting one. Has anyone had success in the long term with crushed coral as a substrate? Layer is very thin, maybe 0.5-1 inch deep.

Edit: Should also mention they use tap water.... i've had no luck convincing them to switch to RODI

 

[Webslinger]

doesn't matter the substrate, whatever they like...I would never think of having any saltwater tank without RODI. It's just going to be a nightmare tank and they will be out of the hobby in a short time.