Yeh, your pool guy nuked it. And capably to quickly achieve what you wanted. He took pH to around 5.0(ish), wiping out the TA, blasted it with chlorine, took it down again after the chlorine went in, then after a day or two, I suspect he put the TA back in with a big sack of baking soda. Just not something TFPers do because of the fallout damage to the bits and pieces attached to the pool, like equipment. It doesn't kill anything on the day, but takes off lifespan. Very glad to hear the heater was kept out of the loop
Fascinating to learn about. Thanks!!
Yeh sorry, the acidity I was talking about is from the pucks, and 21 of them, releasing 3 pucks worth per day, will affect the pool's pH by about 0.1 unit per day (I'm still using 80,000 gallons but have the same doubts). The pool pH may or may not move because of it, depending on a bunch of other factors, but the effect is there, and all good so far. Trouble is the pH of the water in your suction line and its effect on your equipment. You could find that out by shutting down after the 21 new pucks go in (those are 8 oz right?, I think you said large pucks?), then removing the clear lid on the pump above the pump strainer basket, and taking a pool water sample, then checking pH
I think it's important for you to know about, especially given the planned use of the heater.
Many people here would be watching this thread and think... just tell him to get the freakin pucks outta those skimmers.