Trouble increasing CYA level in new pool

[chillin1]

We opened our pool for the first time late last summer, and I've been having trouble increasing the CYA level ever since. It started out just below 30 ppm, which is the lowest mark on the tube in the test kit, so I added 1 gallon of liquid stabilizer, which brought it up slightly to 30. A little later, I added another gallon, which is what was recommended by Pool Math as the correct amount for my pool to increase it from 30 to 50 ppm. The test results still showed it was at 30. That was the end of last season, so I didn't do anything after that. At the start of this season (a week ago) I tested CYA again, and it was still at 30 as expected. I bought 2 new gallon jugs of liquid stabilizer and added one of them, which again is what Pool Math said was needed to raise CYA from 30 to 50. Testing the next day showed it was still at 30, so I added the 2nd gallon and retested the following day. Still reading 30. So in total, I've added 4 gallons of liquid CYA with no change in my CYA readings from the TF-Pro test kit.

I'm not sure what to do at this point. I'm afraid to add any more because I'm not sure if it's a bad reading, or the stabilizer is bad, or there is some other problem. All my other chemistry results are good, except alkalinity, which has been very high (~380) since we originally opened the pool due to the well water used to fill the pool. I've been adding acid to lower the pH and alkalinity a little bit at a time, and aerating the pool to bring the pH back up. The total alkalinity is now around 270, and continuing to reduce. I don't know if the high alkalinity has anything to do with the CYA not increasing. I also have high calcium hardness (~300), which I wasn't doing much about because it's a vinyl pool. Not sure if that plays a role in CYA or not.

Just looking for someone who is more knowledgeable about pool chemistry than me to give some advice on raising the CYA. Just keep adding CYA until the reading goes up, try the dry stabilizer instead of liquid, or fix something else in the water chemistry before adding more CYA? Thanks for the support!

 

[Texas Splash]

1.5 gallons of liquid conditioner "should" increase your CYA by 20 ppm. Disregard the amounts added from season as any CYA numbers certainly changed. All you can do now is start fresh with your testing. If you are sure your 2023 starting CYA was 30 (no lower), then after adding TWO new gallons it should be at least 60 if not closer to 70. But again, if there's a chance your CYA was not truly 30 when you started, it may only be about 40-50. All of this still contradicts what you are seeing as "30" today, so it's still odd. When you do your CYA testing, is it somewhat like the note below?


CYA Testing:
Proper lighting is critical for the CYA test, so you want to test for CYA outside on a bright sunny day. Use the mixing bottle to gently mix the required amounts of pool water and R-0013 reagent, let sit for 30 seconds, then gently mix again. Recommend standing outside with your back to the sun and the view tube in the shade of your body at waist level. Then, begin squirting the mixed solution into the skinny tube. Watch the black dot until it completely disappears. Once it disappears, record the CYA reading. To help the eyes and prevent staring at the dot, some people find it better to pour & view in stages. Pour some solution into the viewing tube, look away, then look back again for the dot. Repeat as necessary until you feel the dot is gone. After the first CYA test, you can pour the mixed solution from the skinny view tube back to the mixing bottle, gently shake, and do the same test a second, third, or fourth time to instill consistency in your technique, become more comfortable with the testing, and validate your own CYA reading. Finally, if you still doubt your own reading, have a friend do the test with you and compare results.

 

[Texas Splash]

I've been adding acid to lower the pH and alkalinity a little bit at a time,

For the TA, a little acid won't do it. Let the pH hit 8.0 then use enough acid to lower the pH down to about 7.0-7.2. Each time you do that it should have more impact on lowering the TA.

 

[chillin1]

@Texas Splash thanks for the suggestions. Those instructions are slightly different than the instruction printed on the card in the test kit, so I tried it that way, but the result is the same. My wife got the same result as well. I'm wondering if the CYA was so low when I opened the pool that adding 2 gallons didn't even get me to 30? It's actually not even 30 right now as I can still see the dot when the tube is completely full, but it's a little blurry, so I think it's close to 30. It's been like that since before I added the 2 gallons of stabilizer, so it hasn't really changed.

 

[PoolStored]

CYA is known to potentially take up to 5-7 days to register. Typical is 24-48 hours. Before you heave more in, give it 48 hours.

 

[chillin1]

So I waited a few days per @PoolStored 's suggestion and checked CYA again. Still around 30. So I added another gallon of stabilizer, waited a couple days, and checked again today. Now it's at 40, so it's finally going up! That's the first time since the pool was completed last summer that it's been above 30, so even though it's taken 5 gallons of stabilizer total to get there, I feel a lot better that I'm not doing something wrong with the stabilizer. Thank you both for your help!

 

[an1vrsy]

One question I have for you is, liquid conditioner separates in the container. Do you rinse the container multiple times to get all of that concentrated CYA goop out of the bottom?

 

[chillin1]

Yes, I rinsed the container several times until it was completely empty and then brushed all the CYA sediment that collected at the bottom of the pool until it was completely dissolved.