Garden fish, can you be more specific? There used to be a product called red devil stump remover - or something like that.
NOT killer, remover...
It wasn't a long acting herbicide.. it was basically a garden safe chemical that was only caustic in high concentration and would speed degradation. As it leaked out of the rotting wood slowly it wouldn't poison anything nearby. That's my goal, targeted destruction with minimal Chance for collateral damage.
Polishing rocks is about mechanical abrasive so borax use in polishing rocks is not related to chemistry. It is very basic, I use it to offset my very soft acidic water in my pool, I believe it functions as a buffer, but I can't recall this time of year.
