Is My CYA Too High or Low or Am I Using the Wrong Terminology?

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asusundevil

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Jun 24, 2014
126
Chandler, Arizona
Surface
Plaster
Chlorine
Liquid Chlorine
Current readings:

FC 3
CC - .5
CYA - 20
TA - 130
PH - 8.0
CH - 350

Most of the year my CYA's fluctuated between 40-50. In looking at the CYA Chart, 20 actually looks to be an ideal area in terms of the requirement of a low FC level. But do I have anything to worry about with the CYA increase.

And I'm thoroughly confused as to how to translate how other posters refer to rising or dropping CYA. Ex:, 3 months ago my CYA was a 40 reading in the test tube. Today that reading is 20. So, in pool vernacular is it "dropping" or "rising?" I ask because technically it's "rising" in the test tube.
 
It's dropping. Since you are in a very sunny area you want to maintain a CYA closer to 50.
 
The first thing you need to correct is your pH. It should never be out of the 7 range. 7.2 to 7.8 is the correct range. Use Pool Math to determine how much MA you need to bring it to 7.2. The water features will cause pH rise, and you need to monitor and correct it as needed.

Next you want be sure that you always keep your FC within the correct range for the CYA. Always target it at the highest level in the range, and never let it get below the bottom of the range.

Use pool math to determine how much CYA you need to add to bring to 50, then put it in a sock that is either hung in front of a return, or put in the skimmer. As soon as you do that, change your target FC level to correspond to a CYA of 50. Squeeze the sock once in a while until it's all dissolved. After about a week, check the CYA level again.
 
Before I head to the pool store, I just tested my CH and it came out to 350. PoolMath is giving shows a general range of 200-400 but with my pool's profile suggests a target of 260. Although I'm within the general range, it appears I'm outside my CH suggested range, correct?

Just dumped some MA into the deep end of my pool to attack the high PH. Will test it again tomorrow morning.
 
You can't do much to control the CH, other than avoid adding anything that adds calcium. As far as being a little high, I've seen my CH levels well over 1,000. About all you can do is drain and replace with water with lower CH level. Water in AZ is all high CH, and with our evaporation rates it will continue to climb. All you can do is keep your pH level right, to help control the CSI (calcite saturation index). You'll find it at the bottom of Pool Math. Once you put all your test results in, it will give you the CSI. If the CSI is below -0.6 (too low) the water will actually dissolve calcium right out of the plaster and grout, damaging the pool. If it's too high (above +0.6) calcium will perciptate out of the water and deposit on surfaces as scale. Several factors combine to give the CSI number including pH, temp,CH, etc. The only one your really have control of is the pH, that's why it's critical to keep pH under control.
 
Picked up some granular stabilizer at Home Depot Saturday afternoon and used the sock in front of a return jet method. Is it common for this stuff to dissolve slowly? Once or twice a day I grab the sock and break up granules but dang it really seems to be dissolving slowly.

I have yet to measure the impact it's having on my CYA because I want to give the stabilizer some time to work its magic. Considering I placed the sock into the pool late in the afternoon Saturday, how much longer should I wait to re-measure my CYA?

I did measure my chlorine loss and I'm averaging about 2ppm a day. It's been averaging a brutal 106 here in AZ so is this a common rate of loss?
 

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asusundevil said:
Picked up some granular stabilizer at Home Depot Saturday afternoon and used the sock in front of a return jet method. Is it common for this stuff to dissolve slowly? Once or twice a day I grab the sock and break up granules but dang it really seems to be dissolving slowly.

I have yet to measure the impact it's having on my CYA because I want to give the stabilizer some time to work its magic. Considering I placed the sock into the pool late in the afternoon Saturday, how much longer should I wait to re-measure my CYA?

I did measure my chlorine loss and I'm averaging about 2ppm a day. It's been averaging a brutal 106 here in AZ so is this a common rate of loss?
Click to expand...

Yes it does dissolve slowly. The more you squeeze it, the faster it will dissolve...good hand workout :handwave: Usually takes about a week to get an accurate measurement for CYA after adding. 2ppm is not surprising in that kind of heat and all the more important to get your CYA where it needs to be as it helps guard your FC.
 
Ok, so I think I made a gross mistake in measurement. Pool Math indicated that I should apply 75oz by weight of stabilizer in order to raise my CYA. The granular stuff I purchased at Home Depot is a container of 5lbs, or essentially 80oz total ounces. Two weeks ago when I added it via the sock method, I used about 1/4 of the container due to not realizing that unopened it came with, again, 80oz. No excuse, I was lazy and didn't pay attention to detail. I just measured my pool and not surprisingly, my CYA hasn't moved at all. Here are the readings as of today in AZ and 113 degree heat:

FC - 4
CC - 0
PH - 8.2
CH - 350
Alkalinity - 140
CYA - 20

So, I'm back to using Pool Math's recommended application of 75oz of stabilizer. And obviously I need to add MA to address the PH. ARGH! I can't believe I wasted two weeks! I guess I didn't realize I would need so much of this stuff. But then again, 28k of pool water is a lot. :shark::-x
 
Do you run the waterfall a lot? That causes aeration and along with your higher than desired TA, will drive the pH up rather quickly. You should probably be testing the pH every few days.

How do you add chlorine?
 
bware said:
Yes it does dissolve slowly. The more you squeeze it, the faster it will dissolve...good hand workout :handwave: Usually takes about a week to get an accurate measurement for CYA after adding. 2ppm is not surprising in that kind of heat and all the more important to get your CYA where it needs to be as it helps guard your FC.
Click to expand...

This is why I always use the liquid. If it's important to get CYA up to levels to protect (and we know it is). I always felt that the faster you do that the better. The cost differential is less than 2x and your pool is 'instantly' protected vs. running another week or more at sub-par levels. Just one person's opinion.
 
jblizzle said:
Do you run the waterfall a lot? That causes aeration and along with your higher than desired TA, will drive the pH up rather quickly. You should probably be testing the pH every few days.

How do you add chlorine?
Click to expand...

I run the waterfall sparingly primarily when have a large group of friends over. I would say once a month for a few hours. I have one of these - see pic below - that runs while my pool filtrates for about 10-12 hours daily in the summer. But here's the catch: It was broken off a couple years ago so it lost its ability to spray and instead produces a yard hose-like effect into the water with some decent amount of bubbles. Could that be the culprit in my high TA or PH?

I add liquid chlorine at night, 128oz 10% jugs, HASA brand, and pour it slowly in front of the return jets. I pour most in the deep end, and the rest spread around the shallow areas. Lately I've been going through 6-7 gallons a week. It's been brutally hot in AZ and my pool is exposed to the sun almost all day.

http://www.lesliespool.com/blog/wp-content/uploads/2013/03/7030B.jpg

- - - Updated - - -

eqbob said:
This is why I always use the liquid. If it's important to get CYA up to levels to protect (and we know it is). I always felt that the faster you do that the better. The cost differential is less than 2x and your pool is 'instantly' protected vs. running another week or more at sub-par levels. Just one person's opinion.
Click to expand...

Great advice. I might pull these two socks full of granular stabilizer out of my pool tomorrow and use the liquid equivalent.
 
Well I've always used the granular CYA but put it in a T-shirt in my skimmer with the pump running continuously and it dissolves large amounts in 12 hours so I can add quite a lot of CYA within a day or two at most and it always measures nearly the full expected amount in the test when I'm done. I've never had to wait a week or anywhere near that amount of time.
 
chem geek said:
Well I've always used the granular CYA but put it in a T-shirt in my skimmer with the pump running continuously and it dissolves large amounts in 12 hours so I can add quite a lot of CYA within a day or two at most and it always measures nearly the full expected amount in the test when I'm done. I've never had to wait a week or anywhere near that amount of time.
Click to expand...

Had not heard of that approach (t-shirt) before. Thank you.
 
You could use a sock or panty hose in the skimmer instead of a T-shirt. I like the skimmer because the water flow is constant (nothing to bob around) and for me it's easier than trying to hang something over a return, especially because I have an automatic pool cover I normally keep closed. Just note that if you do this in the skimmer you HAVE to have alternative suction somewhere such as floor drains or another skimmer or an alternative input pipe into the skimmer. I not only have floor drains, but my skimmer has that equalizer pipe below it so that if the skimmer gets clogged it just takes water from the pool via that pipe directly.
 

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