This is my second year as a pool owner. Last summer we bought a house with a pool and I managed to muddle my way through the last half of the summer. The water turned pea soup green once and was never ever crystal clear. I read up on TFP throughout the winter and have been trouble free this season. The water all summer long has been crystal clear and feels great!
3 weeks ago we had the pool resurfaced with Maui Gem which is a crushed quartz product with a lightly tinted plaster. Looks very nice. Pool was filled with county water which was trucked in 2 hours after the resurfacing was done. The plaster guy had me mix in 3 half gallon bottles of Startup-Tec as pool was filling to help eliminate the plaster dust. The plaster guy also wanted me to put in 12 gallons of muriatic acid which seemed like a lot according to PoolMath. The National Plaster Council recommendation was to keep the pH between 7.2-7.5. The plaster guy said this acid was to help dissolve the plaster dust but the Startup-Tec says it is supposed to reduce the amount of plaster dust. In the end I decided to sort of split the difference and I put 4 gallons of full strength muriatic acid in and brushed several times a day. That night a very prominent rust colored stain showed up in the deep end which was somewhat upsetting since it developed after I put the acid in the pool. There was very little dust and so about 2 to 2 1/2 days later I neutralized the acid with washing soda and borax. Got some liquid chlorine in and raised the alkalinity with some left over Alkalinity Up and continued brushing. Also started bringing the calcium hardness up. Once these parameters were brought back to a good range the stain actually started to dissipate and it is now gone (but it had me really upset for a few days!). The water is crystal clear just as it has been all summer long. You can tell that the drain at 9 feet in the deep end has Phillips head screws in it. I'm telling you all this just to say thank you for all your help. I felt very comfortable that I would be able to do this at least as well as a pool guy thanks to the many years of threads on the forums. Every question I had was answered through research on the forums. So thanks!
Now to the question.
According to the Plaster Council guidelines I could put in some CYA at a week out from the new plaster. I decided to use 2 gallons of Natural Chemistry Liquid Stabilizer which calculated to 34 ppm in my 20,000 gallon pool. I decided to go that route for speed, ease, and no concern about damaging my new tinted plaster. At the time the pH was 7.5, FC 2.5, CC 0, CH 150, TA 80, CYA 0. I shook the bottle and slowly added the contents to the skimmer. I added pool water to the bottle and shook it more to get all the settled product out and also added that to the skimmer. Same was done with the second container. Both bottles were added to the skimmer over the course of 30 minutes. Just for grins I tested the CYA and you could tell there was some in the water at this point but no where near even 20 ppm. I went on my merry way and was adding liquid chlorine all week long based on a CYA of 34. But my chlorine usage was still just as high as before I added the liquid CYA. Last weekend I tested the CYA (a week after adding it to the pool) and again you could tell there was some in the sample but no where near even 20 ppm. I have not performed a backwash since adding the liquid CYA.
Did I get 2 bad bottles that didn't have hardly any active ingredients? I bought it on Amazon and the bottles looked clean with no damage. I don't have the bottles anymore so no way to tell if there was a manufacture date on the bottles and obviously no way to tell exactly how they were stored.
It's now been almost 2 weeks and the CYA is not showing up on my test. Is there any concern that it will all of a sudden show up or would you add the solid CYA now? I have some left over (ie- pre-TFP) trichlor pucks that are in the pool now and I have one bag of left over "shock" that I'll add to boost up the CYA a little.
Any ideas or thoughts?