OK. So I boogered up a with my last bit of reagent. I carried my test kit to work and was checking a co-workers pool sample. His CYA was very high so I attempted to modify the procedure and used up my last bit of reagent. (I only had enough for one test and didn't realize it) So what I did was filled to bottom mark with pool water, top mark with reagent. Then poured half out and filled back to top with pool water. Still high. So I emptied back to bottom mark. Filled to top mark with pool water and rechecked. Still high. Only after the fourth drain and refill with pool water was I able to read 100 on the CYA. Then I checked the "extended test instructions" and duh, realized I was supposed to dilute with tap water. By my calculations I ended up with 96.875% pool water / 3.125% reagent. So can the results be interpolated with my incorrect testing?
Testing procedure for high CYA
- Thread starter CleanSwim
- Start date
You need 50% water and 50% reagent, unfortunately your procedure will not provide a meaningful result.
Fair enough. I will have more reagent by the weekend and can retest for him next week. It's looking like a partial drain/refill is in his future. Thanks!
He might as well start a partial drain now, you know the CYA is over 100 so replacing up to half his water will definitely not overshoot it. Heck, even if he overdid it and lowered his CYA too far, we know how easy it is to raise it back up 
Well there's a pH issue as well. It's really low. Started at 3.0 and he's added some pH up to get it to 5 something. He's going to drain to his yard and is worried about his grass. So I think he wants to get it up a little before doing that. Any experience with a suggested pH before watering his lawn with it? It's a 16K gallon.
I can't say, not a big lawn guy, but my gut tells me that it would be better to bring the pH up first. What is his TA? If it is very low then raising it will help speed along the pH adjustments.
He added some baking soda as well last night. Several pounds I think?? So today his TA was 30. We know that's low. Should he continue to add baking soda to help with pH adjustment. I think he's out of pH up and was looking for Borax on his way home today.
Yeah, I would bring up his TA first and then use the borax. Is he using trichlor pucks to chlorinate still? If so then he is going to want to target a TA of 100. If he is switching to liquid chlorine then something more along the lines of 60-70 will be fine for now.
I don't know what his final decision will be but the trichlor and bad pool store advice got him into this pickle in the first place. I'll advise on the TA adjustment as a priority.
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