CYA 90 - how much water to dump?

[Markpo]

I have a 4 ft above ground pool, 18'x33', the CYA is 90.
How do you know how much water to dump (approximately)?

 

[mknauss]

Welcome to the forum!
How did you test your pool water chemistry? How do you chlorinate?
I suggest you read ABC's of Pool Water Chemistry and consider reviewing the entire Pool School eBook.

 

[JoeSelf]

When I started I dumped half of my water. From 48" deep down to 24". Keep at least 12" of water in.

Use PoolMath fill it out for gallons in the estimating pool volume. Scroll down past the Pool Math Stuff and get your gallons. Put that in at the top of the page. Then put your current numbers from you own test kit in the NOW column. Tell Pool Math what you want your numbers to be in the Target column. It will tell you what to do.

 

[ajw22]

the CYA is 90.

See step 8 in our instructions for the CYA test.

CYA - Cyanuric Acid Test

Cyanuric Acid (CYA) is the chemical name for what is commonly referred to as Stabilizer … Read more…

www.troublefreepool.com

If your CYA level is 90 or higher, repeat the test adjusting the procedure as follows:

1. Fill the mixing bottle to the lower mark with pool water.
2. Continue filling the mixing bottle to the upper mark with tap water.
3. Shake briefly to mix.
4. Pour off half of the contents of the mixing bottle, so it is again filled to the lower mark.
5. Continue the test normally from step 2, but multiply the final result by two.

 

[Markpo]

I used the Taylor pool kit, and I use a combination of non CYA chlorine tabs and bottled bleach.

 

[Markpo]

When I started I dumped half of my water. From 48" deep down to 24". Keep at least 12" of water in.

Use PoolMath fill it out for gallons in the estimating pool volume. Scroll down past the Pool Math Stuff and get your gallons. Put that in at the top of the page. Then put your current numbers from you own test kit in the NOW column. Tell Pool Math what you want your numbers to be in the Target column. It will tell you what to do.

Wow, that's a great calculator! I can't believe I have to dump 56% of the water

 

[mknauss]

non CYA chlorine tabs

I assume those are the cal hypo tablets? Great if you have low CH water to fill with!

 

[Markpo]

So we dumped out the water, added new water and bottled bleach. The pool went from a very dark green to crystal clear in two days.

 

[mknauss]

That's good. But I doubt you have completed the SLAM Process

Did you meet all three criteria?