low alkalinity - correct it or leave it alone?

[rhythm]

Normally the TA in my pool is somewhere between 80-100. Today I did a complete set of tests and to my surprise it measured 60. I did the test twice just to double-check. Now, normally a TA of 60 would likely mean some kind of correction is in order, but in my case I'm not sure. My water here is very hard (fill water is 350-400 ppm) and over time this rises with evap and top-offs. Right now I'm around 750 ppm on hardness. That is why I'm thinking of leaving my TA alone. With my current numbers, the saturation index is already positive (.2 or just barely higher), and raising the TA to the 'normal range' of 80-100 would just make the index higher. If my pH is 7.4-7.6 (and always wants to rise) and my water is very hard, is it OK to have the TA as low as 60?

Furthermore, I'm wondering how it got that low in the first place. I don't think I've ever seen a reading that low since I've had my pool (almost 10 years now).


Thanks,
Greg

 

[JVTrain]

TA will go down with any acid addition or if you were to replace significant water with low TA water.

I would not raise your TA unless it drops to 50 ppm or below and then only bring it back up to 60 ppm, based on your description and your CH level.