I'm looking into a bleach injection system as I would like to automate the daily task of adding bleach. I've read on here where a lot of people are building systems based on the Stenner Classic pump. It looks like a good option but I would like to ensure that no bleach is injected without water flow (older copper pipes).
One way to do this would be to use a flow switch and tie that into the mechanism that turns the Stenner Classic pump on and off to make sure there is water flowing. At the most basic level the flow switch would trigger a solid state relay to turn the injection pump on.
Another method would be to use the Stenner ECON FP pump which already has the mechanism built-in to use a flow switch. This pre-built setup along with it being cheaper ($400 vs $460+$30 for relay both with 15gal tank) is definitely appealing. The motor is also DC instead of AC which allows the electronics to reduce the RPMs of the pump to inject less bleach rather than toggle the pump on and off or using a clutch mechanism (simpler).
I was thinking of using the ECON FP pump to inject a small amount of bleach continuously while the pool pump is running and adjust pool pump runtime and injection pump RPM percentage much like a SWG is used to get the correct FC level.
Does anyone have any thoughts on this type of continuous injection process rather than a set dosing schedule? What about the Stenner ECON FP vs the Stenner Classic?