I’ve had two Woods timers fail on me (causing a serious acid dump, ie, stenner was on for the full time of the pool pump cycle. I really like the Wood timer design and price point, but reliability does become a really important factor in the context of timing the dispensing of acid. So I have two Woods timers - one controlling the other. This at least reduces the odds of another timer failure/acid dump, as this would only happen with a simultaneous failure of both timers. As an additional safeguard against a timer malfunction, I time th dispensing to be during the final 15 minutes of the pool pump cycle. If both timers were to go bad, referring to both going into a always on mode, dispensing would only occur during that pool pump on time frame (ie, timers powered by pool pump circuit).I So I run it at full open without restriction and use a Woods Timer to regulate the time. The Woods timers don't last much more than a year in my experience. I like their precision and price point over the alternatives. I keep a backup on hand.