CYA Issue

dfattfp

Well-known member
Jan 13, 2015
53
Las Vegas, NV
Hi,

So after about 3 years out of nowhere the CYA jumped way up, started getting yellow algae, I've gone through 3 cycles of draining over 3 months, and yet the CYA is still high. If I accumulate all three drain cycles, I've almost drained the entire pool. Why would that be? Can you do it in cycles or do you have to do it all at once? I'm going to again try the actual taylor kit later today instead of the strips. But I don't get it? Any ideas?

TIA!!
 

domct203

Bronze Supporter
LifeTime Supporter
TFP Guide
Jun 3, 2015
3,959
CT
CYA doesn’t just “jump up”, either it was added to the pool, or there is testing error.

Test strips are useless, especially for CYA.

How do you normally chlorinate?
 

domct203

Bronze Supporter
LifeTime Supporter
TFP Guide
Jun 3, 2015
3,959
CT
I use an inline chlorinater using 3" tabs. The interesting thing is why is it staying high (I guess I'll find what the Taylor kit shows).
It’s staying high because you keep adding it.

Using trichlor tablets, for every 10ppm of FC you add, you also get 6ppm of CYA. The FC is consumed, the CYA is not, and continues to accumulate.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
33,318
Laughlin, NV
Use of solid chlorine in our climate is not sustainable, unless you are willing to drain about 1/3 of your pool volume each month.

Get a SWCG. It is by far the most reasonable method of chlorinating using our fill water. You will still have to drain and refill your pool about every two years due to calcium buildup. To reduce that issue, you must run your fill water through a water softener to remove the calcium.
 

dfattfp

Well-known member
Jan 13, 2015
53
Las Vegas, NV
I just filled it and the CYA is high (this time was drained half way), 3 months in a row (not over a lot of time) of draining.

I used to have the salt system, but went to fresh water because the IntelliChlor (IC40) units only lasted about 2 years and expensive each time, still have to drain every couple of years (says salt level high), used more acid, and doesn't work in the winter so have to use tabs anyway. Someone said they should have put in a IC80, maybe that would have made a difference?
 

dfattfp

Well-known member
Jan 13, 2015
53
Las Vegas, NV
The Taylor kit shows it's about 100 maybe 80. I always wondered, when it says when the black dot disappears, do they mean in general or even any shadow should disappears so you can't see anything at all?
 

domct203

Bronze Supporter
LifeTime Supporter
TFP Guide
Jun 3, 2015
3,959
CT
I just filled it and the CYA is high (this time was drained half way), 3 months in a row (not over a lot of time) of draining.

I used to have the salt system, but went to fresh water because the IntelliChlor (IC40) units only lasted about 2 years and expensive each time, still have to drain every couple of years (says salt level high), used more acid, and doesn't work in the winter so have to use tabs anyway. Someone said they should have put in a IC80, maybe that would have made a difference?
I hope you have come to realize that the “tabs” you continue to use are the cause of your CYA issue. Once the water is too cold for the SWG, you should use liquid chlorine, aka bleach.

When you do the CYA test, it should be outdoors on a bright sunny day, with your back to the sun, reading the vial in your shadow at about waist height. I like to fill the vial to the first mark (100) than glance for the dot. If I still see it, I fill to the next line and glance again. I repeat this until I reach a level that obscures the dot when I glance at it. Do not stare at it or your eyes will play tricks on you.

If your CYA is reading 90ppm or higher, you should do an extended test as described in the link below, starting at step #8.

https://www.troublefreepool.com/content/220-CYA
 
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