Need help with new pool chemicals

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Need help with new pool chemicals

Postby cmsulliv » Wed 07 Apr, 2021 14:15

Hi there,

I'm a new pool owner and I've had trouble raising my chlorine levels with both tablets and liquid chlorine. Pool size is about 10,000 gallons. I took a sample into my local pool supply store and these are the numbers:
Free Chlorine: 0.34
Total Chlorine: 0.34
pH: 8.2
Alkalinity: 136
Conditioner: 47
Total Hardness: 314
Metals: Copper/Iron: 0.1

The people at the store have recommended I 'drain and rinse' my pool with a chlorine wash. This obviously sounds expensive. Can anyone confirm that this is what my pool likely needs? I don't know the last time the pool was drained, previous owners did not take great care of it. I live in Arizona and would like to be able to swim in the water safely this summer!

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Re: Need help with new pool chemicals

Postby Denniswiseman » Thu 08 Apr, 2021 03:29

I wouldn't use any more tabs as they have CYA (conditioner) in them and about 50 is OK
Excessive CYA renders your chlorine ineffective and you have to use more to get the same sanitation
For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm
To reduce your CYA you have to do a partial drain and refill
Continuous use of Trichlor/Dichlor will raise your CYA which means you have to raise your chlorine level as well

With a CYA of 50 you need to target 6-8 and a minimum 4 as in Chlorine / CYA Chart
Use fresh liquid chlorine (sodium hypochlorite or plain bleach) as it loses strength over time
You can use Pool Maths to determine how much to use
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Re: Need help with new pool chemicals

Postby Las Vegas » Thu 08 Apr, 2021 04:27

Your pH and Alkalinity are high. You need to add Muriatic Acid to lower those.
2 cups of 20 baume muriatic acid or 4 cups of 10 baume muriatic acid should get you around 7.5 pH.

As Dennis said, your CYA (cyanuric acid) level looks good so I'd avoid using the tablets.

As you stated, your chlorine level is way too low. You're going to want to get your free chlorine level up to at least 6.
This should take at least 3/4 gallon of liquid chlorine to raise your free chlorine to 6.

calcium hardness looks good at 314.

I wouldn't immediately drain and refill my pool; I'd try to get things in order with the current water.
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Re: Need help with new pool chemicals

Postby Teapot » Thu 08 Apr, 2021 07:38

Dont drain and refill, the pool shop are talking nonsense as usual. You have been given good advice above which I agree with.

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