Looking for small bag of calcium reactor media

[Mester320]

I want this to put in a mushroom grow out chamber. Just need enough to cover the bottom of a 8x4 box. I can buy some online but it would be more than I need. Like $10 shipped I am thinking?

 

[ngvu1]

Crushed coral is what you are looking for

 

[Tyreef2016]

Just buy the two little fishes one. It’s nice to replace it every once in awhile as it gets gross.