I have been testing my chemical levels every day for the past 5 days. My FC started at 18 and has slowly decreased to 9. TA has been a constant 50. My pH has been 7.2. Pool Math tells me to add 1/2 an ounce of Borax, and when I do, the pH goes up to 7.6, but then the TA goes down to 30. When I test it 24 hours later, the pH is down to 7.2 and the TA is 50. MY CH is 350, CYA is less than 30 (the measuring device only went as low as 30) and CC is 1.5. My test kit doesn't test for Borate. If I don't plug that in to pool math, will that throw anything off? Only one person used the spa once during these 5 days for about 30 minutes.
260 gal., cartridge filter, outdoor, well water,