Suggestions to keep LSI in check and prevent scaling?

[bobazonski]

The water where I live is very hard, and in the past (before I took over my own pool maintenance) I had significant issues with scaling. Here's what I've done so far to try and address this:

• Replaced the pool water
• Got the TA down to ~60
• Added ~50ppm borates

The issue remains that unless I add around a half gallon of acid per week (I use the Taylor K2006 test kit and add what it recommends based off the acid demand), the pH (and thus LSI) quickly drift upward, while the TA also drifts upward a bit. If I don't do anything for about a week, the pH will climb from 7.0 to 8.0 and the TA will increase by about 10ppm.

It feels like I am adding acid way too often. My questions are, what else can I do to keep the balance in check? Is there anything else I can do, or should I just keep doing what I'm doing? Am I wasting my time/money with adding so much acid?

Thanks in advance.

Today's test results (added acid just a couple days ago):
FC: 5.0 | CC: 0.0 | pH: 7.4 | TA: 60 | CH: 875 | CYA: 55 | Water temp: 90F
Pool volume: ~10,100 gal

 

[mknauss]

I add acid about twice a week during high evaporation rate time. It is all about your fill water. The best move is to use softened water for make up water. Does not reduce the TA from the fill water, but makes controlling CSI easier.

 

[bobazonski]

Thanks for the info! I've only ever thought about the impact soft water would have on CH, but never thought about the impact on TA/pH. This is a good point as our water has relatively high pH and alkalinity levels and probably does explain the imbalance a bit. Plumbing my fill valve to my water softener has been on my list for some time; I guess here is another reason I should try to get that done sooner rather than later. Thanks again.

 

[mknauss]

Using softened water will not reduce your acid use much, as the TA is not removed. But it allows more wiggle room because you can control your CH. The CH in my pool is at 300 ppm. The same it was when I filled it last November after some repairs. I installed the water softener then.