I use these with my RKE. I have 2 of them they are flawless. I use this probe to trigger the CO2 outlet and keep my pH at 7.4.
https://www.amazon.com/gp/product/B001EHJO64/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
Since the pH wants to be high, the PC4 outlet (for the CO2) is set as a "controller" getting its trigger from the pH probe. It goes "on" if above 7.4 with a heuristic of "1". So at 7.41 it will turn on and stay on until the pH registers 7.39. I had it set at 7.0 but was burning through CO2 really fast like 2-3 weeks for 5lbs. Plants seem just as happy with 7.4.I think I'm going to do the same. Do you have it kick on when it hits a certain level then have it shut off at 7.4?
Good question! I had it at a spread of 10 initially and seemed like the CO2 was always on. So I tightened it up to a variance of just 1. I'd say it kicks on every 20 minutes or so and runs for maybe 5-10 minutes. Just an educated guess based on a remembrance of what it is doing when I am down there doing maintenance. I'll try to pay attention more as this would be good information to know. It doesn't hurt it to turn off and on frequently though the solenoid can take it.Oh wow that's a way tighter tolerance than I would have thought. Does it turn off and on a lot or does it take a while for that range?
