I seem to have an unusual situation where my salt level is rising. The pool was completed in March of this year.
I have a SWG pool and the salt was added 30 days after plaster application (StoneScapes) to 3200 ppm (700 pounds) which was confirmed by the salt cell (Pentair IC60) and Taylor 1766 test kit. I have seen a steady rise in the salt level which is now 4300 ppm (confirmed from salt cell and 1766).
I understand that acid additions add salt as a byproduct (I add roughly 1 gallon per week), liquid chlorine's net product is salt (I've added no more than 3 gallons total in this time span), and the SWG's chlorine production doesn't significantly impact the salt level either way. Is it possible that the acid additions alone have added nearly 300 pounds of salt (3200-4300 per Pool Math)?
Most people I have talked to in my area (with the same fill water) seem to indicate the opposite problem (salt level decreasing) which is what I would expect and makes my situation more questionable.
Regardless, here are the numbers:
pH - 7.7
FC - 8
CC - 0
TA - 60
CH - 650
CYA - 80
Salt - 4300
Temp - 74
CSI Range - -0.1 to -0.3
I have never had any scale in the salt cell as I have maintained a negative CSI from the day I installed the cell, so I don't think the reading is an error. All salt tests have read within 100-200 of the reading I get from the IC60. I am also aware that the cells do not actually measure the salt level and they do not correct for temperature variations.
The fill water:
pH - 8
TA - 120
CH - 125
Salt - 40 to 60 ppm (best I could determine with the Taylor test and a larger volume of water) the was later confirmed by the Water Company's quality report (indicated 50 ppm).
Another thought, could high CH levels skew the test and the cell's reading?