I have a cyanuric acid puzzle that has been bothering me for a while. Hopefully someone can help...
First, the background: Bought a house last year with a small (7,500 gallon) pool. I spoke with the (former) pool guy who used to "maintain" the pool, and he readily admitted to dumping pucks in the skimmer for probably the past 5 years. Upon testing, I found (not surprisingly) that the cya was off the charts.
With the pool surfaces looking in pretty rough shape, I decided to have the pool replastered and retiled. I also had all above-ground plumbing replaced, including new cartridge filters.
Upon start-up, stabilized tablets were added to get the cya up to a reasonable level for Texas (about 50 ppm). I used cal hypo to maintain chlorine levels -- no stabilized tablets were added for the past 8 months or so.
So here's the conundrum: Even with no additional stabilized chlorine added to the pool, cya has been creeping up and is now at 100 ppm (according to my Taylor test kit). The good news is the pool is absolutely sparkling and easy for me to maintain by adding liquid chlorine every day (I read up on Pool School and stopped using cal hypo because the calcium hardness was nearly 500 ppm). The pool gets light usage on the weekends only.
Should I care about a high (and slowly rising) cya level or just leave well enough alone?
Also, what is causing cya to rise? Is it residue from the plumbing system?