i have pondzyme but have not used it.,but i am using aquarium bennies and having good results.i'm in my second week of veg and have not switched my rez,and my ph is very stable.also water is very clear considering the temps in my veg tent were 85f +..treat your rez or buckets like a fish tank..if it works for living fish and aquatic plants why not cannabis? this is not my idea i read on another forum and i'm just passing along good info.