I use it in the water. Going to use it as a spray once the buds start getting larger.
I also use it for cleaning 1 - 2 times a week. Add it to some hot water and let it circulate in the reservoir for a couple hours.
I stopped using Hydroguard and Orca when I noticed brown gunk growing on the filter for my circulation pump. Hygrozyme and Cannazyme kept having some kind of reaction to the other stuff in the nute mix, which is why I had to stop using it. The only thing that hasn’t caused the water to turn cloudy and smell is SLF-100.
When I start my next grow I am going to swap out all of the supply tubing, and maybe even the bubbler.