I opened my 5500 gal Intex metal frame / vinyl liner pool yesterday and noticed it was somewhat green and a little slimy on the inside walls. I added two 13.5oz packs of Kem-Tek tri-chlor 67% (60.3% available chlorine) shock and one 1.0 gal 10% chlorine, and ran the filter all day. I also brushed down the sides to loosen up and remove the algae (or whatever it was) and could see it suspended in the water. The water was also too cloudy to see the bottom (~50 inches). At the end of the day, my chlorine reading was only 2.
This morning, I brushed down the inside again and vacuumed the middle. The water is less green, but still very cloudy -- still can't see the bottom. I added another 13.5 oz pack of Kem-Tek shock and another one gallon of 10% chlorine. I ran the filter all day again and at the end of the day the chlorine reading was 3. According to the package, these 13.5 oz packs of shock are supposed to be rated at 2.25 oz added to 10k gal = +1.0 ppm chlorine.
A few hours later, I ran a full test (TFT-1000 kit). My numbers are:
CA N/A (Intex pool)
My questions are: Does the CC reading mean that the chlorine is killing off the algae and/or whatever else organic is in the pool? Will it be caught and removed by the sand filter eventually? Do I need to run any kind of clarifier or flock? Or just keep the chlorine high?
Last year, I had a CYA reading of over 100. I've always heard that it never disappears so I usually avoid the tri-chlor tablets and shock. Why is the CYA reading now less than 20? I've never drained the pool -- just add a few inches of water per week due to evaporation. Does algae or something else dissolve CYA? Does this mean I can stick a bunch of tri-chlor tablets in until I get the CYA back up?
Finally, am I losing so much chlorine because of having no CYA? For 5500 gallons, and what I've added over the last two days, I was expecting my chlorine reading to be 20 or more. I live in Arizona, and it was 100 and sunny today. I get about 6-7 hours of direct sunshine, but I usually only lose 1 point per day of chlorine due to the sun. I am thinking the loss is because of very low or no CYA, and the algae? But for such a small pool, I am not sure if I should be adding so much chlorine.