Pool size in gallons?

[JaySav]

I asked about this a few weeks ago but I’m finally starting to track accurate test results a lot better so need some advice. I thought the pool size was originally 20k gallons, the pool builder couldn’t find the original build paper work but that’s what they estimated it at. With that beings said...

The CYA was 0 so I used pool math and for a 20k gal pool with a goal of 70 CYA it recommended 12 lbs of CYA. Just to be safe I subtracted a 1/3 off of that (to keep math simple since I was unsure of the actual pool size) and added 8lbs. Did the good ol pillow case hanging from the diving board for a day and then hung it from a pool chair while squeezing it infront of the return jet. Finally got it all to dissolve and checked the CYA today (2 days later) and it is 35.

My 2 questions are:
1. Do I need to wait a couple more days for a more accurate CYA reading (I’ve read it can take days for it to get in the system)?
2. Since 35 is half of my goal of 70, I did the math in pool math and that would actually mean to reach 35 CYA by adding 8 lbs of CYA the pool size would be 27k gallons. Is that correct and how it works? Sorry if this is confusing.

 

[Richard320]

According to Effects Of Adding Chemicals at the bottom of poolmath, 8 lbs (128 oz) of stabilizer in 20,000 gallons should raise CYA to 48. So maybe your pool is bigger than you thought, not smaller. If it was me, I'd wait two more days, and brush good every day in case any superfine particles have settled on the floor. If you're still low after that, it's easy enough to add more.

 

[JaySav]

Ok I’ll test again in a few days before adding more. My CH is low also so I’m about to add some of that. I’m just trying to get an idea of pool size so I can accurately add chemicals but for now I will pretend it’s 20k gallons and see what the calcium readings come out to.
Here are my results:
pH: 7.5
FC: 5.0
CC: 0.5
TC: 5.5
TA: 60
CYA: 35
CH: 125
Salt: 3140

I can see the TC level climbing since the CYA has been kicking in so I have been adjusting the SWG to try and find the sweet spot. Thanks for the help!