Slam with high CYA- help! 😩

[katie.e.mccall]

Morning everyone. Finally got in my Taylor 2006-fas/dpd kit. Been battling an off and on green pool since going to the beach for a week in June. Seems like I’d get it ok and pretty clear and blue but over night it would go back to green. Now having found TFP I realize I probably didn’t kill the algae off all the way. Anyway, here are my stats. I know I need to slam but dang I don’t think I can with my cya this high. How would y’all start this process? Also is it dumb to even start now that it’s fall?

Pool details-
22k gallon in ground vinyl pool
350lb sand filter
No saltwater

Test results as of this am-
pH- 7.4
TA-60
CH-140
FC-2
CC-0
CYA- 100

Pool is green, but you can see the bottom. Was using tablets/powdered shock with stabilizer until I found tfp. Since then using liquid chlorine or bleach (depending on what stores have in stock). In July pool store testing had me add 4lbs stabilizer .

 

[proavia]

Whenever CYA tests at or above 90, it's recommended to do the diluted CYA test.

Add pool water to bottom of sticker.
Add tap water to top of sticker.
Mix well.
Pour out half so mixture is to bottom of sticker.
Add reagent to top of sticker.
Mix well, let sit for 30 seconds, mix well again.
Test outside with back to sun and tube at waist level.
Fill to a line on the tube and GLANCE to see if you see the dot.
Repeat until you can't see the dot with a GLANCE.
Pour back into the mixing bottle and do the test a few times to see if you get the same result.
Double the result.

 

[kellyfair]

Not dumb at all. If you close a clean pool at the right time, and then open at the right time, you won’t have to deal with a swamp upon opening.

 

[katie.e.mccall]

ok thank you for the cya tip- is the thinking here that my cya is actually higher? Or that there’s some interference in the basic cya test?

And then kellyfair- this is our second summer with the pool. Last fall “closing” the pool consisted of basically completely neglecting it but continuing to run the pump. If we don’t have a cover what’s the recommended process for closing the pool?

 

[kellyfair]

As a Floridian, closing a pool is one thing I don’t have any familiarity with! Here’s an article that may help.

 

[PieterS]

ok thank you for the cya tip- is the thinking here that my cya is actually higher? Or that there’s some interference in the basic cya test

Yes, your CYA could be substantially higher. Better to check with the diluted test first to see where you're really at!

 

[proavia]

ok thank you for the cya tip- is the thinking here that my cya is actually higher? Or that there’s some interference in the basic cya test?

And then kellyfair- this is our second summer with the pool. Last fall “closing” the pool consisted of basically completely neglecting it but continuing to run the pump. If we don’t have a cover what’s the recommended process for closing the pool?

Diluted CYA test can show higher as the testing vial only reads to 100.

If you aren't actually closing the pool (folks in the northeastern US drainwater, blow out pipes and cover their pools) - continue to run the pump and keep up on testing and adjusting chemicals. As the temps cool down, the FC won't burn off nearly as quickly. You may get by adding chlorine every 7-10 days. But you need to continue to maintain the pool - or you will likely have a time consuming and expensive mess on your hands come Spring.

 

[katie.e.mccall]

Diluted CYA test can show higher as the testing vial only reads to 100.

If you aren't actually closing the pool (folks in the northeastern US drainwater, blow out pipes and cover their pools) - continue to run the pump and keep up on testing and adjusting chemicals. As the temps cool down, the FC won't burn off nearly as quickly. You may get by adding chlorine every 7-10 days. But you need to continue to maintain the pool - or you will likely have a time consuming and expensive mess on your hands come Spring.

Ok awesome to know as far as closing- I’m in southern Tennessee so we’re not swimming during the fall and winter but it’s not cold enough to freeze up either.

 

[proavia]

Ok awesome to know as far as closing- I’m in southern Tennessee so we’re not swimming during the fall and winter but it’s not cold enough to freeze up either.

Yeah- you're not "closing", you're just not using the pool to swim.
Continue to maintain the chemicals and keep the pool clean.

 

[katie.e.mccall]

Ok- finally got to the diluted test. Doing the half tap water and half pool water method (and holding the tube at waist level with back to sun) I got a result of 80 (really it was like 35, which when doubled would be 70). Undiluted result was 100, so I’m guessing I should go with between 80-100?

Since this number is high but not crazy high (like the 300ppm I feared) could I just backwash and refill frequently to slowly dilute it to a more manageable level? Instead of doing a big emptying?