Just opened a newly installed pool the first week of February 2014. Started using the test kit provided by the pool builder but it only tested for Chlorine/PH/Alkalinity. Purchased a new kit which also tested for CH & CYA. However, I questioned the results of the testing using this pool kit. I suspected the testing for certain chemicals was incorrect specifically CH & CYA. I then purchased the Taylor K-2006 and confirmed inaccuracies. However, as soon as I started using this kit, the CH test was in the 550 ppm range. I knew this was high. So, I drained about half the pool and added fresh water. I used water from a source inside the house which is less than 10 ppm CH. (I have a water softener). However, I also tested the outside spigot (which originally filled the pool) and that reads at 150 ppm. My pool CH is now at 340 ppm. The problem is during the drain/refill process the tile was exposed & dried and I had what I believe is scale. Lucky for me, I caught it early and it comes off easy. However, I still have a few questions:
1. Could scale have built up that quickly with high CH (3 month time-frame) - Its important to note my PH was kept in the 7.5/7.6 range and never exceeded 7.8 during this period. In addition, I kept my alkalinity b/w 60-70
2. Is it possible the "scale" is actually salt residue from evaporation. I have a SWG.
3. What would have caused the pool CH to rise to 550 ppm if it was filled with 150 ppm. Could it be the new plaster?
In addition, I try to keep my chemical balance as recommended by TFP for salt pools. In fact, TFP recommendations closely match what my builder recommended. If it were not for the bad CH readings to begin, I would be issue free. The pool is otherwise crystal clear and all the numbers now in balance.