Hi Dale;

I've covered, at various times, why I don't generally like using ORP/pH controllers on pools, and I won't rehash that.

Regarding your situation, what I would recommend is disconnecting the AutoPilot system . . . and the pumps. That means PHYSICALLY disconnecting the feed lines. Feed pumps are often installed in such a way that they can feed 'automagically' and secretly . . . all by their little selves! Until you disconnect those lines, I'm not going to be sure that that's not happening right now.

By the way, you'll need to cap the injection ports. One way to do that is to take a little extra tubing, connect it, fold it a couple of times to crimp it, and use electrical tape to hold the folds together.

Then, run your SWCG and keep up with ANY other chemicals you are adding. Let's see what happens under those circumstances.

Regarding epoxy: it doesn't make the pH go down.

Regarding using soda ash feed . . . I don't recommend it, but you can do it if you really want to do so. Assuming that the AutoPilot system powers the feed pump directly, you can put a NC (Normally Closed) switch between your acid pump and your controller, and then set the controller to 'maintain' 7.4. That way, at 7.4 or below, the feed pump switch will be de-energized -- and thus, the pump will be turned on --but when the pH is above 7.4, the switch will be energized and thus the pump will be turned off. Of course, you have to mess around with the wiring and make sure you get all your voltages right, and purchase the correct switch. But, it's not that hard to do.

FWIW, the full blown commercial ORP/pH controllers all come with a switchable pH control circuit, to feed either acid or base.