CYA 230, replaced 1/2 of water...now 217???

Hi - the reason I detected the high CYA was that I was getting a rash from swimming...and so began the research and I was suspecting pseudomonas.

I had my water tested and was told that the chlorine isn't doing anything at all being that the CYA is too high. This might explain why after shocking a month ago it took 10 days for the chlorine level to drop down to 2ppm. I should mention that my water has no odors, no cloudiness, no green tints or algae - it's crystal clear!!

Background (before replacing water)
- 30000 gallon plaster pool
- Cl = 1.3ppm
- PH = 7.6
- Alkalinity = 160
- CH = 530
- CYA = 230!!!

I then drained almost half the pool, so I'd say I replaced 12000 gallons of water. Then I shocked the pool - and took my water back to the store for testing.

- Cl = 10ppm
- PH = 7.7
- Alkalinity = 100
- CYA = 217????

What the **** is going on here?
For one I don't understand how the CYA could only drop 13ppm after replacing 40% of the water. For two - can someone please tell me what to do from here? The guy at the pool store said "try replacing the sand in the filter". I don't know if he was just grasping at any solution....

Thank you,
Matz

candy - how are you determining the CYA values? Are you relying on the pool store or testing yourself using a reliable test kit? I never could get consistent results from the pool store.

It would be difficult to distinguish 200 from 400 using the Taylor test. I bet your CYA was even higher than 230 before the water replacement.

I would get a good test kit (Ben's or the Taylor) and test yourself to see where you really are now. Be warned though, the CYA test is a bit subjective. There are some good posts on this forum on how to conduct the test for reliable results. Good luck.

BTW - the guy at the poolstore who said to change your sand is a knucklehead.

Thanks for the reply rbonin.

I have a testkit from Leslie's. It looks identical to the Taylor Troubleshoot Kit, except mine has the ability to test CYA and Calcium Hardness as well. I'm basing my 230 and 217 figures from Paddock Pool's testing though, where they use some test strip under ultra violet light. So those numbers are the before and after at the same place.

However, I will say that I tested myself when the number was 230 and it seemed to end up about the same, but when I retested after replacing water, mine came close to 140 or so...which is a guess because the test tube only goes to 100. Maybe mine is more accurate...? I guess I trust the pool store more than my own newbie numbers.

Let's assume I'm right and the number is 140, the store tells me that 30-200 is the limit...but online everyone says 30-50. Which is correct?

Also, do you think that it's likely that I have pseudmonas in the pool when it's clear as crystal?

Thanks!
PS. Sounds like I don't have to add the sand change weekend project to my list

I have seen some information that implies that CYA testing is not accurate over 100ppm, and that it may be much higher than the indicated value.

Quote:

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Originally Posted by Candyass

Let's assume I'm right and the number is 140, the store tells me that 30-200 is the limit...but online everyone says 30-50. Which is correct?

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My 'official' printout from the pool store (Alex - BioGuard) says that 30-200ppm for CYA is ideal. Online I've read that over 50ppm CYA seriously compromises chlorine.

:confused:

TW

The catch with stabilizer is that at higher concentrations, it renders chlorine less effective at sanitizing. Here is a chart that is popular on this site:

Stabilizer . . . . . . . Min. FC . . . . Max FC . . . 'Shock' FC
=> 0 ppm ... . . . . . . 1 ppm . . . . . 3 ppm . . . . 10 ppm
=> 10 - 20 ppm . . . . 2 ppm . . . . . 5 ppm . . . . 12 ppm
=> 30 - 50 ppm . . . . 3 ppm . . . . . 6 ppm . . . . 15 ppm
=> 60 - 90 ppm . . . . 5 ppm . . . . . 10 ppm . . .. 20 ppm
=> 100 - 200 ppm . . 8 ppm . . . . . 15 ppm . . .. 25 ppm

You can see that at your current CYA concentration, you will have to maintain at least 8ppm free chlorine for effective sanitizing. I think most on this site would recommend you shoot for 30-50 ppm CYA, but I guess it depends on how much sun your pool gets. I keep mine at 40ppm and mine is in direct sun all day.

~Rick~

rbonin - I thought it was "dangerous to your health" to swim even at 5ppm FC levels? It says on shock packaging to not swim until FC levels have dropped to at least 5ppm. Which is correct? Is it safe to swim in 8ppm?

Sorry for all the questions - I'm new to this.

Thanks,
matz

What did you use to shock the pool after refilling it?

Donna's Poolboy - I used Leslie's Chlor Brite Sanitizer. Granular shock which I dissolved in a bucket before pouring into the pool.

Picture here: http://www.lesliespool.com/shopping/...rd=chlor+brite

Thanks,
Matz

The Chlor Brite shock you aded to the pool contains CYA adding more to your headache. I think everyone hear would tell you to stick to just bleach.

I'm not the expert on this forum, but on the Chlor Brite website, it says: "Has a built-in stabilizer (conditioner or cyanuric acid)." As you probably know, cyanuric acid is CYA. Depending on how much you used when you shocked the pool, you may had added the CYA right back in.

I have a high CYA level right now (it's a little over 100). Using only bleach, I've been keeping the free chrloine level at 10 ppm and the water has stayed clear.

You say your chlorine level is 10 ppm. Is that total chlorine or free chlorine?

two observations.
Pool stores will tell you that high cya levels are not a problem so they can sell you all sorts of copper algecies and clarifeirs when your pool turns green and they don't want to lose the very lucarive profits they make on trichlor and dichlor!

Testing for CYA is not accurate at levels much over 80 ppm and the sample needs to be diluted and tested to get an accurate result. If you dilute a sample of your pool water with 3 parts distilled water and multiply the test results by 4 you will get a more accurate reading on your CYA level. (assuming your cya is above 200 ppm). Also, from what I have heard, cya CAN deposit on the pipes and in the filter when the levels are very high and it is possible that as the levels drop more is redissolving into your water!

Donnas Poolboy: OH NO! So much for trusting the pool store and not reading the labels. Why would the pool store reccommend this knowing that my CYA is high??? Oh yeah...to make a buck...they're gonna make more than that when I visit them tomorrow :mad: As for the 10ppm level - it's Free Chlorine.

waterbear - thanks for the dilution suggestion - I'll try that and see where it ends up. Either way - it looks like I just spent a bunch of cash on water and accomplishing nothing.

What still puzzles me is that my water is crystal clear.

As far as chlorine levels go I can tell you that in the State of Florida is is permissable to keep a public pool open with FC levels up to 10 ppm!

Quote:

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Originally Posted by Candyass

- it looks like I just spent a bunch of cash on water and accomplishing nothing.

What still puzzles me is that my water is crystal clear.

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Spending a bunch of cash and accomplishing nothing is the reason I found this forum...probably the reason A LOT of people wound up here!

I don't know what to tell you as far as the rash/itchy skin. If your water is clear and you're running 10 ppm then you're doing something right! In your first water test, your CL level was 1.3 ppm. After the drain it was 10. How long have you been running it at the higher level?

You probably don't want to hear this, but you might have to do another water drain. I read on here that someone used a large piece of plastic while draining and refilling. The new water was kept separate from the old by the plastic. That way he was draining only water with high CYA while still adding new water. It also kept from "floating" the pool. (That's assuming your pool is in-ground.)

candy - you have gotten some good advice from these folks. Don't fear the higher CL levels required when your CYA is high. Without this higher level I would expect a green pool, so I too cannot offer an explanation as to why yours is clear. I agree that you need to get your CYA down (to reduce CL costs if nothing else) and there is no way to do this other than a water drain and replace. Try the dilution idea to get a good CYA level reading that you have confidence in, and if it is over about 60ppm, consider another water change. I would not drain more than 1/3 of your volume at one time, to avoid the possibility of "pool floating".

Also, stop using stabilized chlorine... it will just lead to a reoccurrence of this problem. Plain unscented bleach works great.

~Rick~

Quote:

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Originally Posted by waterbear

Also, from what I have heard, cya CAN deposit on the pipes and in the filter when the levels are very high and it is possible that as the levels drop more is redissolving into your water!

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waterbear, are you saying that the pool store guy that I called a knucklehead might actually have a point :rolleyes: ? Maybe changing his sand would help reduce CYA? Please say it ain't so :) .

~Rick~

Quote:

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Originally Posted by rbonin

waterbear, are you saying that the pool store guy that I called a knucklehead might actually have a point :rolleyes: ? Maybe changing his sand would help reduce CYA? Please say it ain't so :) .

~Rick~

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Like I said I have heard it from a few different sources. Don't know if it's true but it certainly might be. This case here is either proof or is just inaccurate testing because the sample wasn't diluted and the concentration was so high.:confused:

I tried the dillution method waterbear suggested, by taking 1 part pool water and 3 parts distilled water. The CYA then came to 35, then multiplied by 4, so according to this reading my CYA is 140. This is way more in line of what I would've expected after the water change. I'm still puzzled by the pool store's reading, but it makes sense if high CYA becomes inaccurate to read.

Thanks everyone - I'm taking my first "test-swim" this weekend, in 10ppm of FC, so I'll let you know if the initial problem, the rash, is solved....if I don't return though...I hope it's not from Chlorine Intoxication ;)

I'm new her too but last year I had the same problem and emptied pool to no avail. I went to a different pool store and guy said to put in 10 to 15 gals of bleach. I did that and no problems since.

I would still drain again.

Knock that sucker (cya) down further.
140 is too high and your going to need to maintain a FC level that is high.
I have spent a summer swimming in 11+ppm FC as a result of high cya with no negatives effects.
I never really felt comfortable about it, but It was what was necessary.