200 is basically where my tank hovered, too, before ozone. The ZEObak additive has increased this to t stable range of 350 to 375, it seems. Thus far, it's stable.
I treat ORP the same, btw. And with a Profilux wlan system, I can and do access the tank from a distance, as it gets left in the capable (?) hands of the alarm monitoring company when I'm away! If the orp alarm goes off (which I've set to trigger if the orp varies by 50 points in either direction), I can look at other parameters on line and make a call to one of my "fish friends" if I'm away. I have to say: thank the dear lord for auto top off, which has enabled one to two-week trips away from home without having to hire fish baby sitters.
The alarm company responds if the flood sensor in the fish room is triggered -- which is their own sensor that links into their monitoring system. Handily, instead of having one of their security guards come out (if I can't be reached), one of my fish buddies is on their call list. I just couldn't imagine a security guard looking into my fish room and having the faintest idea what to do. It looks like something the borg would've built to take a pee or something equally waterbased but subsequently burdened with gadgetry.
Erik