Glue safe for dwc unit(fastening air stones)

Can anyone tell me with a safe kind of glue to use in a dwc application for fastening air stones onto the bottom of your resevior, can anyone tell me what I should use, I was thinkin a hot glue gun because u can take it off if u need to change. Any thing that works would be great and FYI I live in canada, pce

no type of glue i dont think, but there are many types of silicone sealent that can bve used, google em and you'll find some that are meant to be used in aqariums and are animal safe with no chemicals so those should be fine