My 45mp2 is on its way (10 gpd/25psi), along with Stenner's 15 gal. tank. Will time it separately from the pool pump with Woods 50015 Outdoor timer. Set up is to address PH creep from a SWG pool as dual spill over spa creates a lot of aeration andabove average acid demand (notwithstanding having made a career out of TA adjustments). I am going with a fixed rate pump vs variable to cut down on part maintenance and possibly avoid sound issues (clicking as some have reported).
As most threads relate to injection of Chlorination, I am hoping to improve safety margins if possible to minimize risks attendant with leaks caused by an issue with one or more of the components of the system. So here is what I'm thinking. Feel free to weigh in if you have any other suggestions or to point out flaws.
1. Line leaks: I am going with the 1/4" UV tubing, and assume this will be appropriate for MA. (BTW, anyone know if MA causes greater tube breakdown than Chlorrine?). Since annual tube replacement appears to indicate this as a primary breakdown point (potentially), annual replacement of the tubing sounds like a must, to be sure. But I'm thinking of also running the 1/4 UV tubing through, say, a 1" clear tubing. I'd use a little silicon adhesive at the hook up ends or even fashion a simple rubber collar. Then Iíd insert a T in that clear line, attach a line to it and run a drain line back to the tank to carry any tube leakage. My house backs up to a canyon so I am concerned about rats chewing through my 1/4 line. Again, I would be less concerned if the line were only to leak chlorine.
2. Insertion Point: I will not be syncing the Stenner pump to my pool pump. With risk that an out of sync system will have acid being pumped into 2" pool lines that are not moving any water, I plan to place the insertion point as far downstream as possible - perhaps just before the return line heads into the ground. My thinking there is that this location means there will be a considerable amount of PVC pipe between that insertion point and my heater (with my SWG configuration thankfully adding to the overall length of PVC pipe from insertion point to the point the pipe enters the heater). Normally, I would prefer to have he insertion just before the SWG so as to let the normal acid injection help clean my SWG cell; but should there be build up of acid from an out of sync running of my Stenner Pumo, my heater is just too close to the SWG - I'd hate to have acid concentrated water backing into my heater in that event.
3. Check Valve: The 45MP2 does not have the built in check valve but I guess thatís why Stenner sells an inline check valve. Still am unclear if check valves are a weak link (blockage) and not sure about that potential). Anyways, my understanding is that if there should be any Stenner pump tube leaks, water wonít pump it out of that tube leak opening under the force of the running pump. I understand this is the reason for a check valve. But given my set up (See #1 above), Iíll need a check valve so that a tube leak doesnít end up pumping water into my proposed second outer ďbackup safety tube and then into my acid storage tank via the overflow line set up referred to in the #1 configuration above).
4. Safeguard Against Out of Sync Timer: I have a Aqua Logic AQL - PS4 automation with an empty AUX 1 relay. Not sure, but I donít see why I canít have my Stenner Pump Timer (Woods 50015 Outdoor timer) powered from this relay, which of course will pass power to run the Stenner pump per what I program it to run. I believe the AUX 1 relay has a timeclock capability, which I would then set to coincide with the timing of my pool pump. If the timer should screw up and want to run the Stenner Pump at midnight, for example, there would be no power to do so, since the AUX 1 relay would be timed to be off when the pool pump is not running. The only weak link might be that the Woods Timer, when not constantly fed with power - as will be the case for about 18 hours - will not hold its settings. If that is the case, I guess I would have to find a better battery back up timer that would hold the settings for a longer period (ie the 18 hour the timer does not have juice to it). I guess I could just hook up the Woods timer to my pool pump relay instead to feed it power whenever the pool pump is on; but I have some concerns that I could exceed the draw rating of that pool pump relay and possibly burn it out if I am pulling power both for the pool pump and the Stenner Pump. The foregoing reflects my lack of sophistication in matters pertaining to relays and their draw capacities, among other of my knowledge shortcomings.
No doubt, some of this might be considered overkill. And Iím sure plenty of you have run your acid injection system without issues or thinking any of this is even necessary. Thatís understandable and reasonable. But I hope to hear from those of you who can help me with flaws vs. being overly cautious (the latter being an element of my nature).