A quick update on this thread - I have started to pull the pH back up. The base demand test showed 8 drops to get the pool to a pH of 7.0

I did a bucket test and figured out how many teaspoons were in a pound of Borax and am going to the store to buy 20 lbs to start with. I also measured the pH of the water coming out of our well - yikes! Very high calcium hardness and pH above 8.0 - I might do an acid demand test on the well water to see if this has been the ongoing reason for our need to add acid all the time and now also dealing with calcium scale.

Lastly, I started aerating a few days ago. I have an oilless compressor and connected it to the return line through the Chlorine canister plumbing at about 5 psi on the regulator. Gives a nice plume of bubbles out of the two most shallow water inlets.



I replumbed temporarily to take the heater out of the circuit while doing the Solution #2 treatment.

The Jack's Solution #2 acid bath removed about 50% of the scale and what is left is quite a bit easier to remove now by scraping with a plastic dish scraper. I can tell that it also affected the Hydraazo finish - when you rub it with your hand, it feels slightly slimy and you can see a light dark cloudiness in the water around the area you rub so I think that is the pool surface being attacked along with the scale.

We are having our son's senior graduating class (only about 20 kids) over for a senior night pool party next week so time to bring this back into balance and get it ready for summer use. I'll keep the Alkalinity low as suggested and work to keep the pH in the 7.2 range and see of the scale disappears the rest of the way on it's own.