So glad to be a member of this amazing forum!
Our pool is less than a year old. It is a chlorine pool that holds 17,000 gallons. We have had a very easy time maintaining the chemistry of the water these past 10 months. Unfortunately, I accidentally forgot to add chlorine a couple weeks ago and the pool sat at zero FC for about a week. Algae grew -- no! It wasn't a bad case obviously, but in my haste to fix the problem, I added two packets of Aqua chem shock (which contains dichlor -- I realize this is a huge no no now!) Our CYA levels went from about 40 to 100 with the addition of those two packets of shock. I took my pool water to Leslie's to have them test it and verify it. They too couldn't believe that the packets of shock raised it so high, but it was true. We immediately rented a sump pump and drained out about 7,000 gallons of water from the pool and refilled it this weekend. The only thing I have added is muriatic acid to lower the PH down to 7.5 so I could SLAM it. We added bleach this weekend and the algae is gone. I tested the levels today and was SHOCKED to see that our CYA is still at 100! How is that even possible? Am I missing something? Help! ( I feel like I just wasted a lot of time and energy for no results.
Thank you in advance.