Sand And Substrate Fertiliser

[danlock10y]

I was thinking of using JBL aquabasis under sand and was wondering if it would stay under or if it would get dug out by cories?

 

[JoshuaA]

Cories tend to only skim the surface they don't dig so to speak. I have used an under layer substrate for some time and not even come close to having a problem with Corys digging. I am however not familiar with JBL aquabasis so I can't comment on it that much apart from if it needs to go underneath I'm sure the sand will keep it down.