cya is 90, have to replace 50% of pool water?

Dec 16, 2012
33
I am a newbie - last year was first year with inground pool and I think I did okay but I admit I have not been testing the water often recently other than PH. I just tested CYA for the first time in a long time and it was 90. I put a target of 45 in pool math and it says replace 50% of the pool water with new water. Is this the only solution??? I don't like having to spend money to replace that much water. If I have to do this should I do it ASAP or should I wait until mid May when I hope to start using the pool again. Please advise, thanks!

--- I just read in another post to not use chlorine tablets. Well I stopped using bleach and was using packets of shock (was leftover from previous homeowner so i was trying to use them to save money) to keep my chlorine level high enough over the winter and I guess that may have backfired?
 
Hi Matthew and Welcome!

Yes, as it stands that is the only option. I would suggest that you start working on it now rather than later.

Have you looked into the water cost? Typically is really isn't very much.

Lastly, may I presume you now how you got to 90 PPM Cya?
 
I assume I wasn't testing it enough so it just got higher and higher because I never added anymore CYA since the beginning of last pool season? using packets of shock to chlorinate over winter was a mistake? thanks for the info!

I think I'm going to have to call a pool person because I am unsure on how to dump half the pool water out. :(
 
Dittos to what Patrick & Jason stated above - a partial drain & refill is the only practical way to lower the CYA level.

Matthewmon said:
Well I stopped using bleach and was using packets of shock (was leftover from previous homeowner so i was trying to use them to save money) to keep my chlorine level high enough over the winter and I guess that may have backfired?
If the packets of shock contained either dichlor or trichlor then, yes, this would have increased CYA. If the shock packets contained calcium hypochlorite, that adds calcium and will temporary turn the water cloudy for a day or so.
 
I think I'm going to have to call a pool person because I am unsure on how to dump half the pool water out. :(

Each pool is a bit different, but on *my* pool, if I wanted to drain water out I'd use my valve handle to close off the skimmer and leave the main drain (the drains down low) wide open. I closed the skimmer so as to not suck in air through it when the water lowers below it.
...then after cutting my power off, I'd turn the multiport valve handle on top of my sand filter to the "waste" setting, and then turn the power back on.
...then I'd let it go (just like as if I was backwashing, except on "waste" it bypasses the sand entirely) until it got down the desired amount.
...then replace the missing water with my fresh fill water.

Sometimes people have to do this a few times to eventually exchange all the water in their pool for metal or cya free water. Just be careful not to drain too much at one time as that is risky to the pool to be too empty. Draining 1/3 should be no problem. If I wanted more out I'd drain-refill-drain again-refill, rather than risk going too far at one time (I'm cautious like that :) )

Another option is to use a small sump pump (comes in handy for various pool purposes, so worthwhile to buy IMO) and just drain it that way. A third way to drain is to use a simple garden hose to siphon it down if your yard is sloped enough.
 
You can go to waste as Yippe says. Backwash some before you are done, but not more than you normally would with a regular backwash. Doing that excessively isn't good on your filter.

Second option is to rent a sump pump from Home Depot and use that.
 
thanks for the info guys! I'll try what you said Skippy. When I just turn it to waste and turn the pump on the water comes up out of a drain in my yard and floods it so I can only do a little at a time and it would take weeks to remove 1/3 pool water lol. I'll try your method.
 
I don't know what it will cost to rent one, as suggested, but I recently purchased a small pump from Harbor Freight.
I don't have the receipt handy but I think that I spent $75+_. It attaches to a standard 1/2" garden hose, that you can feed into a sewer clean-out.
I don't know where you live, but some areas really frown on sending pool water into the storm drains, as it feeds directly into local creeks, etc...

just a thought
 

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there is a pump thing that pumps underground water out near my regular pump. they pool guy said it was a good thing to have. maybe it can be used to pump out water or is it only for the underground water - pool guy said to use it after a big rain. I can plug it in but don't know how to turn it on???? The pool guy used it before but I have never used it...
 
To join the chorus -- I bought a 1/6 hp pump from Harbor Freight for around $40 (was on sale and with a 20% off coupon), connected that to 2 hoses in line (150-200' in total?), and ran it to the cleanout in the front yard. It took 2+ days to drain 1/3 of my ~20k gallons, but there was no rush so it didn't matter. Doing it again i would buy the next higher pump (1/4 or even 1/3 hp), as the flow was a lot slower with all that hose than I had expected.

In my area water isn't expensive, so refilling the whole pool would only be $30-$40, but YMMV. It's worth doing a one-time drain to get things where you want them; in general my understanding is that if you follow the methods here you won't usually need to drain often if at all after that.
 
I just closed off the skimer and the water is still coming out of the drain in my backyard? I guess I need to get a sump pump does it come with a hose to get the water all the way to the street?


I just had to drain for the same reason as you. Except my CYA level was probably well over 200.
I used the 1/6 sump pump from harbor freight. Put it on the top step and pump into your sewer clean out. I would drain down to the point of almost losing suction, then I would start filling with another garden hose at the bottom of the deep end.



My pool is approx 27 k gallon. So I had to repeat the process over a couple days.
 
My process was basically what Yippee and TK did. Waste/refill over several months periodically last season, only taking the water level down to that of the skimmer; now my CYA is around 45, down from a high of 100+. And I use bleach exclusively, no more pool store visits for me!

Edit: I highly recommend the TFT test kits; this basic tool is a requirement of you want to keep your pool in top shape

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