Yet another CYA question....

[LovingArizona]

Since I found TroubleFree for pool help AND drained 80% of my 5 year old water and replaced...pool is back to beautiful. Now comes the fun part of learning the better way to balance that this website is teaching me.....

Guess I dumped out too much of my CYA 200 water in my 24,000 gallon/Tucson AZ/cartridge filter pool...test I just took after letting the water settle and circulate with nothing but lots of liquid 12% chlorine is CYA of 5. So....
I need to raise the CYA so I'm not adding 2 gallons of chlorine every day in 95 degree weather...but I have already spent so much $$$ between hockey puck chlorine at Leslies and the pool refill...spending more for adding CYA seems like major insult to injury...so...I would like to use my full 35lbs of triclor pucks up to raise CYA. I must have missed it, but I've looked high and low for a calculator to let me know exactly how much CYA each puck releases so I hit the sweet spot low end and go no higher with CYA. I have an auto chlorine dispenser, so I loaded it up with 10 tabs along with some additional 12% liquid..FC is over 5, but I suspect that will be back to zero by tomorrow with as warm as it is until I get the CYA nudged up....

Long story to get to: How many pucks total to get a good low end CYA?

 

[jblizzle]

How did you get a CYA of 5? The test only goes down to 20ppm?

Bottom of poolcalculator.com in the Effects of Chemicals section ... Leslie pucks are 8oz of trichlor (I happen to be using some as well). Make sure your volume is correct at the top.

You need to keep a close eye on your pH getting too low when adding all those pucks at the same time.

Please add your pool details and location as described HERE as it will help us help you.

 

[LovingArizona]

So sorry...think I got all my details in my signature. We have a local shop, EKonomy pool, that is a locally owned place of pros...so I'm going by their reading they gave me of my CYA this morning. Since I dumped out easily 20,000 gallons out of 24,000 10 days ago, that reading seems about right...especially since my FC is pretty much gone every morning...and I've been testing at home every morning....

 

[Richard320]

Where'd you get the original CYA reading that caused you to drain 20,000 gallons? Maybe it was wrong, too?

For 24000 gallons, 35 pounds of trichlor pucks will raise FC by 160, CYA by 97, and lower pH by 8.56.

So you won't be able to add them all at once, to put it mildly.

2 four pound canisters of CYA will set you back about 35 bucks and take you up to 45 CYA.

 

[GuinnessPhish]

if you're still going to the pool store to get your water tested, you're doing it all wrong.

 

[LovingArizona]

Sigh. I'm talking shorthand on this post, if you are curious, here is my original post on TFP that led me to draining out water to begin with...believe me, it was the RIGHT CALL....
the-pool-chemists-here-are-amazing-t58931.html

So...I have spent so much money on getting this pool ready for the summer already, I'm just trying to be smart here on out. I will buy my own CYA test kit after our next paycheck, till then...from what I have learned on this website over the last couple of weeks, the low CYA reading makes total sense.

I was just hoping to be pointed to a good gauge of the Leslie's CYA per puck content since I bought the 35lb tub BEFORE I knew my CYA was through the roof.

 

[GuinnessPhish]

Trusting a pool store's testing is highly unreliable. Until you get that proper test kit ( http://tftestkits.net/TF-100-Test-Kit-p4.html ), you'll never know if what they're telling you is true.

 

[LovingArizona]

And...I know not to add all 35lbs of pucks at once, my dispenser won't hold that much at one time (LOL)....but since the CYA doesn't go away, I was just trying to get a gauge of how many to add over the next few weeks(along with the liquid chlorine to keep my FC at the right level) before I stop adding pucks.

Is that making sense?

 

[Richard320]

And...I know not to add all 35lbs of pucks at once, my dispenser won't hold that much at one time (LOL)....but since the CYA doesn't go away, I was just trying to get a gauge of how many to add over the next few weeks(along with the liquid chlorine to keep my FC at the right level) before I stop adding pucks.

Is that making sense?

Yes, it makes sense. The problem is that those pucks will keep lowering pH, and until the CYA gets up to a certain point, you'll lose the FC to the sun almost as fast as the puck dissolves. Consider that with zero CYA, chlorine in the pool has a half life of about an hour. Meaning if you add 12 ppm in the morning, in an hour you're down to 6, 2 hours later, 3, 3 hours later 1.5, and by the time you get home from work it won't be detectable!

Maybe split the difference. Add a bottle of CYA now, and feed the pucks to the pool to finish raising CYA. A four pound canister - Lowes sells it, you don't need to go to the pool store - will bring you up to 25, and then you can stuff the dispenser until you've burned through however many it takes to raise CYA to where you want it.

 

[LovingArizona]

THAT is helpful, thank you, Richard. Around 10am my FC was over 5...I'll check again in an hour or so and see how much as burned off. Adding straight CYA just seemed like insult to injury with the wrestling match I've had with this pool water over the last few weeks...but I understand there has to be some in there or else I need a chlorine factory on site ;-)
The PH seems to be bouncing around a bit with the liquid 12% chlorine...I add acid to get it down to 7.0-7.2...then a week later it's creeped up to 7.8+...so I'm keeping a close eye on that, too.

 

[JasonLion]

Any pool store that tells you that CYA is 5, or 200, is suspect. None of the common CYA tests are accurate in either of those ranges.

The PH tends to go up when your TA is too high. I didn't see you mention your TA level, but it seems likely that it is too high.

 

[LovingArizona]

My TA is 90...I have fresh 10 day old water. I took 3 water samples of the old, green, murky water to two different pool stores to test...one test was all pool water, the 2nd was a 50/50 pool to fresh distilled water mix, the 3rd was a 25/75 pool to distilled mix all came back(after allowing for the dilution or lack of) in the 200 CYA range....I know, I know..everyone here will hate me and yell at me until I get my OWN test kit.....I simply have to wait till next month to order the one suggested in pool school.....

(To be clear...the very first CYA test, full strength pool water, was 100. I knew that could not be right, so I went to the 2nd pool store with a 50/50 mix. That also came back at 100 CYA. It wasn't until I had a 20/75 mix tested that came back at 40 that I knew I was roughly in the 200 CYA range...sorry for not being more specific.)

 

[Richard320]

THAT is helpful, thank you, Richard. Around 10am my FC was over 5...I'll check again in an hour or so and see how much as burned off. Adding straight CYA just seemed like insult to injury with the wrestling match I've had with this pool water over the last few weeks...but I understand there has to be some in there or else I need a chlorine factory on site ;-)
The PH seems to be bouncing around a bit with the liquid 12% chlorine...I add acid to get it down to 7.0-7.2...then a week later it's creeped up to 7.8+...so I'm keeping a close eye on that, too.

That's hard water. Get used to it. I add acid 3X/week.

 

[LovingArizona]

Yep...I am used to it. The first time I dumped the water when we first moved into this house with the pool 7 years ago, the TA was...eh, I don't remember exactly, but it was so high, it was impossible to get the PH down. AZ water is very hard out of the tap...just look at anyone's faucets and showers that don't have RO or water softeners