Well, looks like I'm replacing all of the water (CYA: 600+)

[skacey]

I emptied and refilled my pool at the beginning of last season (December 2019) but my numbers are well off the chart and I can't keep chlorine registering without several bags of shock.

Chlorine: 0
Free Chlorine: 0
PH: 7
TA: 120
CH: 2500+
CYA: 600+

I've never seen CH or CYA so high. The Pool Calc said to replace 93% of the water.

I live in Las Vegas, so hard water is typical. But holy cow, those numbers seem insane after one year. I'm guessing I need to resurface, but can't really afford to do that right now.

 

[Texas Splash]

Yikes! That's up there. Is that your own testing? I don't see a test kit in your signature. Well, now is probably as good a time as any before that Vegas Valley sun peaks. Maybe rent a sump pump that can suck it out quick then refill in hours of darkness? As expected, the CH may still be relatively high (500 - 600 maybe), but the CYA should be next to zero once exchanged. After that, no more tabs or bags of shock and that will never happen again. Liquid chlorine only unless you get an SWG.

 

[skacey]

Yikes! That's up there. Is that your own testing? I don't see a test kit in your signature. Well, now is probably as good a time as any before that Vegas Valley sun peaks. Maybe rent a sump pump that can suck it out quick then refill in hours of darkness? As expected, the CH may still be relatively high (500 - 600 maybe), but the CYA should be next to zero once exchanged. After that, no more tabs or bags of shock and that will never happen again. Liquid chlorine only unless you get an SWG.

Yep, I get it.

My last pool was completely BBB including a bleach injector. When we moved, I just got tired of hauling jugs of bleach and switched back to tabs. Lesson learned.

For reference, I tested using the Taylor K-2005 kit. The CYA was milky white and the first pass only took about 6-8 drops before the dot disappeared. I had to dilute it to even get close to a reasonable measurement.

 

[Sunnydaze]

Ha. And a very popular pool guy I found on YouTube before I found TFP said that it's ok to use dichlor and trichlor year round because it will take many, many years before the CYA gets too high. But he also uses only test strips and says he only gets concerned about CYA when it gets closer to 300. I can't believe pool owners pay these guys to service their pools.

I did some of my own calculations using pool math and if I used 2 pucks of trichlor per week and 1.5lbs of dichlor to shock each week, it would add over 250ppm of CYA in just 6 months.

 

[DeanP66]

People back east or in colder climates can get away with pucks and high cya sometimes because they are always exchanging water either through backwashing with a DE or sand filter, or when they winterize the pool and lower the level. Plus, we see people come one here saying that all their CYA disappeared over the winter from ammonia, so they basically get a fresh start without having to do full water exchanges.

 

[an1vrsy]

Here in Las Vegas where we get no significant amount of rain, our make up water from manual fill or autofill will only add to the high CH numbers unless we plumb the soft water tank to the fill line.

 

[DeanP66]

It's the same for me here in San Jose. My fill water is CH 350 so last year when I replaced our ancient water softener, I also plumbed it to my pool fill line and it makes a world of difference. Now my CH hardly ever moves.