Total hardness

[goz63]

So I have been balancing my pool after the pool guy hired by previous owner mucked it up. Had to do a water swap to get CYA down from 150. My well water I used is VERY soft with a calcium level of 25. Used app to add CaCl and got it to 200. Added recommended amount to go to 220 and stayed 200. A week later now 175. We have had some rain but I don’t have a leave and no one is swimming right now. Anyone have any idea why Ca level is dropping?

 

[Texas Splash]

The CH test can be a bit tricky and there is a small variance allowed. Are you using a speedstir? Are you ensuring the water sample goes all the way to light baby blue? If you are using the 10ML sample size and multiplying each drop by 25ppm, it only takes one drop difference. Either way, I'd just monitor it for now. With your FG pool, a CH of 175 is plenty. Now if the CH continues to drop, I would expect other levels to drop as well - especially the salt. If they both drop, then there's something to be concerned about.

 

[goz63]

That makes sense. I didn’t want the CH to get too high for scaling. Salt is holding rock steady. I don’t have a speed stir yet. On the list.