Easiest way to lower CYA

[Mklpatrick]

I had my water tested at a pool store and my CYA level was at 140. The sales guy there said I could lower it by diluting the water. He suggested that I:
1. Shut pump off for 24 hours
2. after that time period, place a garden hose at the bottom of the pool and just let it run for 10 hours, or so

He said the CYA would just drain out of the overflow drain and the fresh CYA-free water coming in at the bottom of the pool would replace the depleted water. I’ve never heard of this method. Does this sound correct?

 

[PoolGate]

This would work a little but you are better off draining 50% of your water and then refilling. It should put your CYA at 70, which is an ok number. Another method is to put a tarp on the pool and fill on the top while draining on the bottom. How are you testing? Pool store testing is typically inaccurate. Also there are some dangers to removing water from a pool. Fill out your sigline with your pool details will help a lot. here -> https://www.troublefreepool.com/account/signature

 

[MiguelACA]

I had my water tested at a pool store and my CYA level was at 140. The sales guy there said I could lower it by diluting the water. He suggested that I:
1. Shut pump off for 24 hours
2. after that time period, place a garden hose at the bottom of the pool and just let it run for 10 hours, or so

He said the CYA would just drain out of the overflow drain and the fresh CYA-free water coming in at the bottom of the pool would replace the depleted water. I’ve never heard of this method. Does this sound correct?

I had a "leak" on my overflow, it created a vacuum at some point and was siphoning the water out of my pool. My autofill was keeping it in check. I never really noticed a water level difference until I tested my chemical levels and noticed I had been adding CYA WAY more often than i should've been.

So yes, tossing a hose in the bottom and letting the overflow dump out the excess and diluting will work. Might take some time over just dumping half and refilling, but it will work. I remember someone talking about the water in the pool and the water from the hose being different temperatures and how that affects how they mix.

 

[V___25]

Sounds like a version of the No Drain Water Exchange except that method pumps it out while replacing with fresh water.

Draining - Further Reading

www.troublefreepool.com

But before you do anything, you should confirm that number with your own test kit.

Swimming Pool Test Kits Compared

What pool test kit should I buy? Why not use test strips? Our recommended test kits will pay for themselves in no time!

www.troublefreepool.com

 

[Mklpatrick]

Sounds like a version of the No Drain Water Exchange except that method pumps it out while replacing with fresh water.

Draining - Further Reading

www.troublefreepool.com

But before you do anything, you should confirm that number with your own test kit.

Swimming Pool Test Kits Compared

What pool test kit should I buy? Why not use test strips? Our recommended test kits will pay for themselves in no time!

www.troublefreepool.com

Actually I just did. It’s about 130. I’m using a Taylor K-2006, by the way.

 

[IceShadow]

Not sure how you got 130, but if you did a diluted test and got a result of between 60 and 70, it's somewhere in that neighborhood. Replacing 50-75% of the water sounds like the right way to go.

EDIT: I would test how long it takes to fill a 5 gallon bucket so you know about how long to run the hose.

This method also relies on your fill water being much colder than the incoming water. If they're close to the same temp, then you want to use a pump to drain from the bottom and a hose in a bucket on the top step to fill simultaneously. The fill water will likely be less dense than the pool water unless there's a big temp differential.

 

[Mklpatrick]

Not sure how you got 130, but if you did a diluted test and got a result of between 60 and 70, it's somewhere in that neighborhood. Replacing 50-75% of the water sounds like the right way to go.

EDIT: I would test how long it takes to fill a 5 gallon bucket so you know about how long to run the hose.

This method also relies on your fill water being much colder than the incoming water. If they're close to the same temp, then you want to use a pump to drain from the bottom and a hose in a bucket on the top step to fill simultaneously. The fill water will likely be less dense than the pool water unless there's a big temp differential.

It was over 100 so I just guesstimated and assumed the 130 at the pool store was correct. The new water I’ll be pumping in will be at least ten degrees colder than the pool water.

 

[ajw22]

It was over 100 so I just guesstimated and assumed the 130 at the pool store was correct. The new water I’ll be pumping in will be at least ten degrees colder than the pool water.

For CYA > 90ppm, 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 adding R-0013, but multiply the final result by two.

If you need to dilute the pool water further then apply these ratios:

Pool water	Tap or distilled water	Multiply result by
1	1	2
1	2	3
1	4	5

Note that when doing a diluted test not only do you multiply the range of the test you multiply the error rate of the test, so results are a ballpark - not an absolute.

See CYA Testing for tips in how to read the test results.