Does Boric acid tend to lower over time in hot tub? Or only with splash out or water removed?

[duganderson]

I just removed and 1/5 of my water and replaced with fresh water in my 400 G pool because my salt level crept up too high for my salt water generator. I added 3 oz. of boric acid to bring my boric acid level up 10 so it's hopefully now at 50 again.

Does boric acid slowly get used up, evaporate or reduce over time OR is it only removed with splash out and water removal? (I'm assuming it does NOT evaporate). Thanks! Doug

 

[Mdragger88]

Splash out or water replacement are the only way borates are removed as far as i am aware. @JoyfulNoise may have more insight.
So long as you are between 30 & 50 ppm they should be plenty effective. I only dose my tub upon fresh fill & don’t have any issues managing ph at the end of my water’s life around the 5/6 month mark. I get quite a bit of of splashout.