Warmer, sunnier days... Getting ready for swim time.. CYA


Well-known member
Sep 15, 2018
Seminole, FL
So, over the winter we've just been using the spa occasionally. Running the pump a couple of hours a day at relatively low SWCG percentage was enough to keep chlorine levels good, and adding acid as needed kept the pool nice and balanced.

Now we are getting warmer, sunnier days, and a LOT of pollen. Chlorine use is up, and I am finally going to try to get the CYA levels in the right range. Dot is visible at 30, but only just, so I'm guestimating 20.

Full disclosure: I am one of those folks who HATES the CYA test, and can never really tell, to my satisfaction, when the stupid dot disappears. I'm thinking about getting a pool store test done just to confirm my estimate.

Poolmath says adding 6 pounds will raise my CYA by 42. I was thinking of doing that, then tweaking after a day or two. I have 8 pounds from Amazon arriving today.



Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
Add 4 lbs of CYA wait 3-4 days after it dissolves then retest. See where you are towards CYA 60-70.

For CYA, salt & CH better to add about 2/3 and retest and get to your target in a few doses.


Mod Squad
LifeTime Supporter
Jan 17, 2012
Evans, Georgia
You know how the directions say to have the sun at your back, and hold the tube waist high??

Ever see a pool store employee go outside to test this??

Right. Neither have I.

'nuff said.


Silver Supporter
Aug 22, 2017
West Palm Beach/Florida
I also try to do this test around the same time of day. For me that usually means around 11am. I also make sure it is very sunny when I do the test. I look for my shadow to be directly in front of me. Then shake the bottle and start squeezing. I am in the same situation as you. Just raised my CYA to 70. Pool looks great.


Bronze Supporter
Oct 20, 2017
South-Central WI
I am one of those folks who HATES the CYA test, and can never really tell, to my satisfaction, when the stupid dot disappears.
I think everyone hates that test, but it's the most reliable one so far for CYA. Maybe one of these days someone will figure out how to make it a titrating color change test like the rest of them. That would be awesome

When I got my refill from TFTestkits, I threw in the CYA standard for like $3. It's filled with a water solution that has 50 ppm CYA in it. You can check your testing technique, or fill to the 50 ppm line and see what the dot looks like when the test is complete (a very foggy blob you can see if you stare but can't see with a quick glance).

I was pleased to note that the fill, glance at waist high method outlined here on TFT worked and I successfully "tested" 50 ppm on the 50 ppm standard. It was well worth the $3 or whatever it cost to add that standard to my order to have peace of mind I was testing right.
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Bronze Supporter
Nov 30, 2019
Pawleys Island, SC
I find it much more convenient and just as accurate to perform the CYA test right at the garage workbench where I perform all the other tests. I used the Taylor 50ppm standard CYA test solution to establish a consistent 'disappearing dot' sight picture with the 50ppm test, barely visible at 40, gone at 50. This is with a 4' double tube LED workbench light more or less overhead. I look for the dot from about a foot away. Consistent conditions is the key, not, IMO, indirect daylight or a particular position to eye or body. I also don't have to let weather or time of day dictate whether I can test CYA or not.
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Gold Supporter
Bronze Supporter
Oct 25, 2017
Ocala, FL
You just wanted to show off the SPARKLE water and pretty mural! Looks awesome!
Oh geez, I thought that was real water!

Im with you, poolnoob. I am DYING to get in that pool. Its killing me to have not ever even been in my new pool yet. The temps are just teasing me...not yet...not quite yet....not yet.....