Extremely high CYA levels

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C

chillycheeks

New member
Apr 4, 2024
2
Australia
Hello,

I've recently become the owner of a pool for a house we just bought. Problem is I've never owned one. Now, we noticed the colour was cloudy and green over the last few days and got someone to come by and take a look. They think the issue was algae growth, luckily it was mild. Our pH was 6.9, FC around 4, TA 120 however our CYA was 230!!!

I'm wondering what to do, apparently the chlorine is ineffective at high levels and I really really don't want to drain the pool and restart. Can I put in algaecide and wait for CYA to drop? Can I just use liquid chlorine for the next few days to clear the algae?

Any options appreciated.
 
Hi!

Welcome to tfp !!

the only way to reduce Cya is drain and fill. Even if you have to do partial drain/fill numerous times
( Ive personally had this same problem)

What type of pool do you have? I’m sure others will chime in soon, to offer guidance

there is no quick fix for high cya.
Maybe spend a little time reading info here on tfp. Your cya needs to be under 100 or chlorine can not do its job . Period.
Cya over 100 is a moot point
(please don’t listen to the pool store )
Without a sanitized pool you are open to a whole host of problems

Good news is, it’s fixable and you can manage it yourself
I’m not sure how to link the article but search this site for:
“The free chlorine and cyanuric acid relationship”

Good luck
 
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Welcome! :wave: Coupled with the fact that to lower an elevated CYA you have to exchange water, you also have the algae issue to contend with. Any algae is bad algae and will only get worse. For that we use the
SLAM Process.

At this point we have to be careful about making some assumptions until we know more about your pool, how you typically chlorinate, and how you test the water. Accurate water testing is the foundation of everything we do here at TFP. In your area, members reach out to Clear Choice labs for a good kit.

I'm going to tag a couple members from your area like @AUSpool and @mgtfp who might like to share some local experience as well.
 
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Please understand what algeacides do & don’t do.
They are a preventative at best but they don’t sanitize the water nor will they take care of an active algae problem.
So even if the water looks clear if there’s not enough chlorine in the pool in relation to your cya the water is unsanitary.
Also - many algaecides contain copper which you absolutely don’t want in your pool.
While cya does degrade a little overtime it is a very small amount- a few ppm per month. This means it could take years for it to go down to a reasonable level in your case.
Since you have algae you need to do the
SLAM Process - this is impractical to carry out at cya levels over 80ppm. It’s ideally done at 30-40ppm cya.
The good news is that a water exchange can help with both the cya problem & subsequently the algae problem as you’ll greatly reduce the organic load while you’re at it making the slam process easier to accomplish.
As mentioned above you must first have a proper test kit at the ready to know exactly where you stand & be able to complete the slam

Pool Test Kits - Further Reading

www.troublefreepool.com www.troublefreepool.com
Here’s some info on draining/water exchange options

Draining - Further Reading

www.google.com www.google.com
 
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Welcome to the forum!

Not much to add for now, step 1 really is to get a Clear Choice Labs test kit, then we can take it from there.

The high CYA and low pH indicate use of trichlor chlorine tabs and probably dichlor "shock". You definitely want to change over to liquid chlorine, and eventually you want a Salt Water Chlorine Generator (SWG).

Until your kit arrives, add about 5ppm worth of liquid chlorine per day. You can calculate the required amount with PoolMath.

I suspect you'll have to drain most of your water, but let's wait for that test kit and then we'll talk you through the next steps.
 
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chillycheeks said:
Hello,

I've recently become the owner of a pool for a house we just bought. Problem is I've never owned one. Now, we noticed the colour was cloudy and green over the last few days and got someone to come by and take a look. They think the issue was algae growth, luckily it was mild. Our pH was 6.9, FC around 4, TA 120 however our CYA was 230!!!

I'm wondering what to do, apparently the chlorine is ineffective at high levels and I really really don't want to drain the pool and restart. Can I put in algaecide and wait for CYA to drop? Can I just use liquid chlorine for the next few days to clear the algae?

Any options appreciated.
Click to expand...
You are in the right place. I was in your position several years ago. After wasting money I learned that a drain and refill was the only way. Manage your cya level yourself and use chlorinating liquid. The algaecides are not necessary. Good.luck.
 
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Hello,

I posted a thread a few days ago about my problem with algae in my pool with a CYA of 230!

The concensus was it needed to be drained

Now I have a fibreglass pool, and I've heard stories of them popping out of the ground when drained.

I'm wondering what the best way is to drain and refill for the purposes of lowering its CYA

Is is approximately 25000L

Thanks in advance!
 
The link was given in your other post, but easy to overlook so here it is:

Draining - Further Reading

Study the "No Drain Water Exchange" section. It does take a bit of study - but essentially is pumping "bad" water out at the same speed as you can add "good" water. The study part is to set it up to minimize in the pool mixing of the two.
 

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