Everyone has their own way of doing things, so I'll just lay out mine. Many like h2o2 as a regular additive, but I personally feel like it should be reserved primarily for emergencies. I also like hygrozyme, but not so much in conjunction with Zone or even in an active hydro system so much. Many use it that way though. As far as the h2o2, it's an indiscriminate killer - it will perform miraculously at the task of cleaning up root problems if used right, but it also leaves the roots themselves somewhat damaged and weak - leaving them more vulnerable to the same sort of stuff you were trying to get rid of. They'll look good, so it's misleading somewhat. This is part of why you'll hear some people suggest that once you use it during a grow, you may need to keep using it. It also runs it's course pretty quickly (2-3 days before it's effectiveness is seriously reduced) and requires more frequent add-ins if used as a regular additive. So, I leave it for emergency root problems as a last resort. Many others do this differently, and that's okay, this is just my take and what I do.
"Zone" is said to have some chloramines in it, but I'm not 100% sure of everything it has in its makeup. Dutch Master is notoriously secretive about what goes into their products beyond listing what they need to for legal reasons. I do know that one of the main things that makes it work is Copper (Copper Sulfate I believe). Copper is deadly to algaes, bacterias and even plants in high enough doses. But, in the right doses very effective at maintaining a healthy rootzone. Enzymes can live harmoniously with "Zone" but I don't think they are necessary to use together personally. I've only used it a couple of times in the Flo N Gro, and had a bit of a hiccup so now I just stick to "Zone" and during veg... I use Root Magic between reservoir changes. For my coco coir plants/moms, I typically use hygrozyme and Root Magic, without the Zone. Though, I've done coco coir with Zone in the past, too.
I use Zone weekly, and I believe in weekly reservoir changes. Sometimes due to "life happening" I'll stretch it to 10 days before a change, and I've gone as far as 2 weeks, but I wouldn't go 2 weeks on a regular basis personally.
My recommendation would be to keep it as simple as possible as far as root zone treatments. If you want to be "sterile" then, I still think Zone is your best bet (without hygrozyme and h2o2). Alternatively you could use beneficials like mycorrhiza with or without enzymes like hygrozyme.
Again, some of this info people have passionate feelings in other directions. But, this is where I've landed after much trial and error and watching others trial and error (and a little reading up).
Hiker, thanks for sharing what's working for you. I appreciate you weighing in. I hope you don't take my thoughts as being critical to your regimen, as far as h2o2... but, you might want to try just the Zone at some point to see how that works out. The other products can add a layer of complication and/or cause some other issues inadvertently so that's something to consider as well.
Please let me know if I missed anything or if something needs more illumination.
