Please Help Me

[JasonLion]

Testing CYA levels over 100 is somewhat speculative. All of the CYA tests that work that high have rather low precision, so your test results are probably something around +-30, or possibly worse.

With CYA at 150, normal FC levels are around 12 to 18. Measuring PH at those levels is a little challenging, as the PH test starts to be off above an FC of 10.

 

[dbabz31]

So what do you suggest we do? In what way does a high FC make your PH levels inaccurate? With all the draining and the refilling we have done, I would have thought that the CYA level would have dropped more. Please advise me what you would do if you were me. With a FC of 4, which is a loss compared to the store results from a couple days before, what would you do? If there is a loss of FC, then doesn't that tell me that the pool is not "locked"? We need to keep the FC high if the CYA is high in order to have excess FC to work on bacteria,etc right? thanks for your help.

 

[duraleigh]

Please advise me what you would do if you were me

That's VERY easy. Continue to drain and refill until your CYA becomes manageable.

Oh, one more thing. You need a good test kit.

 

[dbabz31]

We drained and refilled twice prior to closing our pool for the winter. So the 2 times plus draining to close and then allowing for it to refill with rain and snow makes it three. How could our cya have been so high, that even with the 3 times of draining it still remains high? If my cya is high, then please can you explain why i would have FC loss overnight? I would think that any chlorine would be bound to the cya if the cya was high. At this point, the pool is very clear and my levels this morning are as follows.
FC=3
CC=0
ph=7.9
TA=230
Cya= hard to truly tell because the slash marks on the test tube only goes to 100. I stopped with the drops and the water level was between the bottom and the 100 slash mark.
I understand the idea of needing to keep my FC at a higher number in order to have chlorine be effective. But then how can there be a loss if my chlorine is low? Are they any other factors that could be giving me a false high CYA? Thanks for any information.

 

[bobodaclown]

Is this the test your using for CYA?
http://www.taylortechnologies.com/produ ... deshow.asp on the bottom there is a link that shows how to do the CYA test.

 

[duraleigh]

Are they any other factors that could be giving me a false high CYA

Nope! Unless you are performing the test incorrectly and your description sounds like that is not the case.

Thousands of people have been following the methods described on this and other forums for several years.....IT WORKS.

Until you get your CYA well below 100, you are spinning your wheels. An acceptable alternative for you might be to search around until you find a pool store that tells you your CYA is fine, but it's not.

 

[Bama Rambler]

Back in Sept of last year you said you got a test kit. Which one was it, and are you still using it to test the water?

The pool stores like to use the term "chlorine Locked" but there's really no such thing. What happens is that the CYA gets so high that you can't maintain a high enough FC level to kill the algae and they call it locked. Even with very high CYA some of the FC gets released from the bond and gets used up so you lose FC all the time even if the CYA level is extreme.

There are only two ways to lower the CYA level. Water replacment or Reverse Osmosis! Since R/O isn't available to you, you'll have to drain and refill till your CYA gets to a reasonable range.

 

[dbabz31]

to bobdaclown.. yes that is the procedure i did. I bought the taylor kit. So Bama, you are saying add chlorine to keep my pool from turning green, but drain it first? If we drain and refill, what is the amount of time after reflling that we should wait to test cya again? 24 hours? and what about the FC? how long after refilling do i retest in order to know how much to add to get it to 15 or so? Have you ever heard of having to drain and refill this much? How could we go all summer last year with no problems and then have such a high cya in what seemed such a short time?

 

[JasonLion]

After a partial drain and refill the water can be tested again after an hour with the pump running. That applies to all the levels, including FC and CYA.

We see pools with these extremely high CYA levels, requiring a lot of water replacement, a couple of times a year.

CYA can go up slowly from trichlor usage and not cause problems right away. Sometimes by the time you notice it the CYA level is already quite high. CYA can also go up quite quickly from using dichlor to shock the pool a couple of times. We also get people who have been having problems from high CYA levels for years, but had no idea it had anything to do with their CYA level.

 

[dbabz31]

well ok then we will have to drain it again. would you drain it then add the chlorine or chlorine and then drain...seems like throwing money out the window to do the latter. but it we can drain it and let mother nature help with refilling that would be great. according to the pool calculator if i want to get my cya to 80 i need to drain half the water! we know that our mistake was not know about cya as a by product of the chlorine sticks we were using. we also were using packages of shock...all adding more cya when we first saw algae. thanks for your help.

 

[Bama Rambler]

I would do the drain and then add chlorine. If you're expecting rain today then just wait till after to test and add chlorine. Just be aware that it takes a lot of rain to make much difference at all in the level of the pool.

 

[chem geek]

How could our cya have been so high, that even with the 3 times of draining it still remains high? If my cya is high, then please can you explain why i would have FC loss overnight? I would think that any chlorine would be bound to the cya if the cya was high.

Your CYA got so high because you used stabilized chlorine sources such as Trichlor tabs/pucks and/or Dichlor powder/granular. For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases CYA by 6 ppm. For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm. With 2 ppm FC per day chlorine usage, then Trichlor tabs will increase CYA by over 35 ppm PER MONTH.

As for how a high CYA can give you such a high overnight FC loss, it is precisely because most of the chlorine is bound to CYA that very little active chlorine (hypochlorous acid) is present to kill algae faster than it can reproduce. This is also true for nascent algae growth that may not be visible (i.e. not yet dull or cloudy water or visible green algae).

If your CYA is high, but not extraordinarily high (i.e. if it's in the 100-ish range), you can operate at high FC levels, but shocking the pool gets a bit impractical. Nevertheless a "slow shock" at 20-30 ppm instead of 40 ppm would be better than nothing. Then after the nascent algae is killed and your overnight chlorine loss rate drops, you'd maintain at least 8 ppm in the pool at all times, assuming your CYA is 100 ppm (if it's higher, you'd need proportionately higher FC). Of course, the best thing to do is more water dilution to lower the CYA further.

 

[dbabz31]

i have heard that the cya should be tested at room temperature. Does it make that big of a difference if it is tested when the water is cold? With us having drained it 3 times already (not total drains but enough that the steps were not covered, how high do you think our cya got? is it possible that the cya increased over the years since we got the pool? thanks for the information. I feel like I understand cya at times and then I get confused at times because I just dont understand how we can have any FC if our cya is so high right now. I would think that it was bound up.

 

[JasonLion]

You can bring the water sample inside and let it warm up first and then test for CYA. Cold water can slow down the reaction that makes the water cloudy, giving false low readings, if you don't wait long enough. So the test is more reliable if you let the water warm up first.

It is very likely that the CYA level has increased since you got the pool. Several different commonly used products contain CYA, notably the common chlorine tablets/pucks (trichlor) and most granular "shock" (dichlor).

The FC test measures the total FC level, including any FC bound to CYA.

We hear about pools with CYA levels over 300 fairly regularly, so still being over 100 after three partial drains in not extremely unusual.

 

[dbabz31]

I used the pool calculator and it tells me to drain about half of my water again! Seriously? Once we get the cya levels down, then we shock until no overnight chlorine loss right. Second step after that, we look at ph,etc. I am thinking that we should never ever use the chlorine sticks or containers of shock like we have been for the 2 yes we have had the pool. No one ever told us about testing cya. once we get a handle on this, how often do you think we should test cya? do you test it if you start to notice FC loss overnight? our pool looks clear, but you are saying we could have invisible algae. Great! Why do they even make the products that contain cya if it never goes away unless you have massive amts of water loss? I cannot believe that we would have to drain half of our water to get cya down.

 

[JasonLion]

When CYA is over 100, draining and replacing 50+% of your water is an excellent idea.

We don't recommend using trichlor (tablets and sticks) or dichlor (granular shock) except in special situations.

Once CYA is under control you only need to test it two or three times a year.

There are very few ways to get chlorine to be stable enough to be safe to handle. One of the most effective is binding it to CYA. The annoying part is that the pool industry doesn't make any attempt to explain the disadvantages of that approach.

 

[dbabz31]

Do you think that it is possible that there might have been cya in the water we had trucked in? I am on well water so I have no idea what chemicals are in the water that is trucked in. Just a thought. So once we get this cya down, there is no need to use anything but liquid chlorine when we need to add chlorine. Unless our cya is low when we open it each year. This is so expensive! It is killing us.

 

[JasonLion]

No, there wouldn't have been any CYA in the water you had trucked in. CYA is not in either ground water or municipal water supplies.

If you don't use any product containing CYA, the CYA level falls very very slowly over the course of an entire pool season due to splash out and backwashing. Most years a single small addition of CYA in the spring provides all the CYA you need for the entire year. Every now and then there might be enough rain, and thus water pumped out to lower the water level, to require adding more CYA mid-season, but that is unusual.

 

[zea3]

The water that was trucked in did not contain CYA. Water that is trucked in generally comes from a municipal source. It may have trace amounts of chlorine, but CYA is not added to drinking water.

Once your CYA is at a workable level, you should only use liquid chlorine.

 

[dbabz31]

So just for the heck of it, i took the same sample of cya that i did last night and reused it today to see what the levels are. it came out to closer to 100. then took a new sample of water today and it gave me 120-150(hard to say exactly). it thought that a warm sample would have given me a false low reading...or is it because the mixture was already done? I guess there is no way around this but to drain the pool. i tested the other stuff today...need to just get this done before i get algae. I know there is something brewing because my levels were this today.
FC= 0.6
CC=0.2
PH=7.9
Cya= high over 100.
Thanks for letting me know about the trucked in water. I guess I am just wishing we would have drained the whole pool last year and brought in a entirely new water for the entire pool. probably would have saved us money in the long run. Thats what i just cannot grasp...Its like we put in enough new water to equal and entire pool, so why isn't it lower? Well gotta go get some liquid chlorine so i will be ready to shock once new water is in. Will come back when we got it done with new numbers.