Green pool, high CYA

[Tsraaron]

Hey everybody,

I just got my Tf-100 test kit and was planning on performing a SLAM on our pool to address the green water problems it's been having. First test I performed was the CYA test and it maxed out at 100. I did the diluted test and it came back at 110. How much water should I drain and refill to bring that down to the 30-50 range?

 

[gonfishin]

You can use the PoolMath app or web calculator (see link at the bottom of the page) to figure this out.

Looks like 55-75% of the water needs to be replaced.

 

[proavia]

Welcome to TFP!

What is the CH? When is the last time the pool was fully drained?

With the diluted CYA test, was it between 50 and 60 and you multipled by 2? We always round CYA up as the scale is logrithmic not linear.

 

[Tsraaron]

Welcome to TFP!

What is the CH? When is the last time the pool was fully drained?

With the diluted CYA test, was it between 50 and 60 and you multipled by 2? We always round CYA up as the scale is logrithmic not linear.

Thank you

Haven't tested the CH yet. The pool was fully drained about 6 months ago actually.

The diluted CYA test was half way between the 50 and 60 marks so I went with 55 and multiplied by 2 to get the 110.

I'm guessing the CYA is high from using too many chlorine tabs over the summer.

 

[ajw22]

You need to do a drain or the No Drain Water Exchange Process with 60% - 70% of your water to get it down to 30-50.

 

[Mendy48]

Thank you

Haven't tested the CH yet. The pool was fully drained about 6 months ago actually.

The diluted CYA test was half way between the 50 and 60 marks so I went with 55 and multiplied by 2 to get the 110.

I'm guessing the CYA is high from using too many chlorine tabs over the summer.

Yes! you CYA will increase when you use chlorine tabs over the summer. You may want to refrain from using Chlorine tabs in the future and just stick with adding Liquid Chlorine/Bleach in you pool the old fashion way.

The only time I use Chorine Tabs is if I'm going on vacation as I do not have a SWCG pool.

As far as draining your pool, I'll go with "water exchange" instead. Follow the link aj sent you.

 

[duraleigh]

Test both your fill water and your pool water for CH. Since you need to drain/refill to reduce your CYA, it MAY make sense to reduce your CH if it is waay up there and your fill water will bring it down.

Like others have said, a 50% drain/refill is likely all you need but I would confirm both refill and pool CH values while I was at it.

 

[proavia]

It would be more cost effective to drain "x" amount rather than do a water exchange since you are in the Phoenix area. Our water table is very low here. Chances of floating the pool are slim, unless you back up to the foothills.

As Dave suggested, test your fill water CH - I'm betting it's around 250ppm or so - and pool CH. Do you by chance have a water softener?

With a CYA of about 110-120, you can drain about 60% plus or so to get your CYA down to around 50.

Hopefully you will be moving away from the chlorine tabs (pucks, trichlor). Use either liquid chlorine or consider installing a SWG. Continued use of tabs will raise your CYA to unmanageable levels in short order.

 

[Tsraaron]

Test both your fill water and your pool water for CH. Since you need to drain/refill to reduce your CYA, it MAY make sense to reduce your CH if it is waay up there and your fill water will bring it down.

Like others have said, a 50% drain/refill is likely all you need but I would confirm both refill and pool CH values while I was at it.

It would be more cost effective to drain "x" amount rather than do a water exchange since you are in the Phoenix area. Our water table is very low here. Chances of floating the pool are slim, unless you back up to the foothills.

As Dave suggested, test your fill water CH - I'm betting it's around 250ppm or so - and pool CH. Do you by chance have a water softener?

With a CYA of about 110-120, you can drain about 60% plus or so to get your CYA down to around 50.

Hopefully you will be moving away from the chlorine tabs (pucks, trichlor). Us
e either liquid chlorine or consider installing a SWG. Continued use of tabs will raise your CYA to unmanageable levels in short order.

Just tested the pool water for CH and it's at 325. The fill water is 125.

No water softener but we are in the Ahwatukee foothills area.

We were using both liquid chlorine and the tabs but I think the tabs just got used too much. Safe to say I've learned my lesson now and I'll be using more liquid chlorine after learning about all this stuff.

 

[duraleigh]

That's very nice fill for Arizona. Your CH presents no issues. I would suggest you drain about 50% of your pool water, getting your CYA down to around 55......that's just about ideal for your climate this winter.