HIGH CYA

[trickecat]

I'm new to pool ownership and I've learned a lot from this board. I finally got a decent water testing kit that includes a CYA test (using advice from the site). I show a CYA level somewhere between 500ppm and 250ppm. I did the test initially and it was nowhere near the register so I mixed half tap water and it still didn't get to the 100 mark so I dilluted to 1/4 and finally got reading between 60 and 80. Is this high of a CYA even possible? Is it safe to swim with that much CYA?

I'm showing FC = 4 (after adding 3gal bleach)
CC = 2
PH = 7

BTW, my pool is crystal clear and gorgous but I'd really like to keep it that way.

Thanks in advance for the advice!!!

 

[UN1017]

Welcome to TFP!

It is possible to have a very high CYA. You said you are new to pool ownership. Does that mean you just moved into a house with a pre-existing pool? You have high CCs which has a direct relationship with a high CYA levels/chlorine effectiveness. If you can give us a set of full test results and specs of your pool that would be great.

At this point based in your CYA you are going drain most of your water an refill. Get us the info and we'll get you in heading the right direction.

 

[GuinnessPhish]

drain and refill....

or partial drain and refill

 

[trickecat]

Thanks for the help! We moved into a house with an existing pool in September, a few weeks later we closed the pool. As I understand it the relo company had let it turn to a swamp sometime in August but by the time I got it the water looked fine. I used a Wal-Mart test kit for that last month and didn't track anything but PH and "Chlorine". I've calculated the pool to be 25k gallons. It's rectangular, something like 35' by 16' with a 8' deep end. Tests this morning were:

FC: 0
CC: 2.8
PH: 7.2
TA: 90
CH: 330
CYA: At least 250 (half dilution was a 1/4 inch below the 100 on the test)

I'm going to take some water into leslie's to validate before I drain. I'm thinking about being conservative, drain out a little over a foot and see if it comes down to something managable. If I stop using tablets and am backwashing as part of weekly cleaning shouldn't the CYA slowly drop through the summer (weekly backwash being the key b/c it doesn't exit any other way)?

Welcome to TFP!

It is possible to have a very high CYA. You said you are new to pool ownership. Does that mean you just moved into a house with a pre-existing pool? You have high CCs which has a direct relationship with a high CYA levels/chlorine effectiveness. If you can give us a set of full test results and specs of your pool that would be great.

At this point based in your CYA you are going drain most of your water an refill. Get us the info and we'll get you in heading the right direction.

 

[Charlie_R]

With that high CYA, plan on several 1/3 drain and refills. I hope your water isn't too expensive where you are at.

 

[Suziqzer]

I wouldn't count on Leslie's giving you any more accurate information. Their test won't be accurate for CYA and won't go near your levels.

Best bet is to drain much of your water, refill, retest and see where you are. Wish there was a better option, but there is no other way to get rid of CYA and I wouldn't even want to try and maintain a pool at that high of a level.

It's a good idea to put your pool information in your signature line so people helping you know what kind of pool you have.

 

[tim_pool_newbie]

You mention you were/are using tablets. I assume you're referring to Chlorine tablets. If so, that's part of the reason for increased CYA levels. If you truly follow the BBB method, you'll learn that those tablets fight against themselves as although they are good for slowly releasing chlorine, they also contain CYA which as we all know, too much of is a bad thing as it blocks the chlorine from doing it's job. I suggest you stop using the tablets immediately and only use liquid bleach/chlorine instead.

I also don't believe a weekly backwash is necessarily required. Don't know what filter type you have (I'm only familiar with DE), but you only need to backwash once the filter is no longer being effective (i.e. pressure climbs too high). It doesn't filter out any of the CYA though. Only water replacement will accomplish that.

Good luck!

 

[JohnN]

Just to let you know, if your CYA is on the high end of your estimate (500) you will need to replace about 90% of your water to get down to 50. If your CYA is at the lower end (250) you will need to replace 80% of your water. For a CYA of 250, you should never let chlorine get below about 19. For a CYA of 500, you should never let chlorine get below 38. Although I think I remember chem geek saying something about chlorine levels can be lower when the CYA is excessively high.

 

[trickecat]

Thanks for the advice! As one poster predicted the leslie's CYA test used less reliable methods than I had at home (a test strip). They had it at 150 though. I've drained down below the first step and am starting to refill. If my high estimate are right it's likely I'll be going through this process again (if I end up needing to drain 90%). Any common troubles I should look out for on the refill and rebalancing of chemicals?

Thanks again.

 

[Charlie_R]

Just keep what you can of FC in it, and watch your pH. You might want to order a couple of extra bottles of R-0013 when you order your TF-100 or K-2006. You will probably be going through a lot of that.

Other than that, the rest can be rebalanced once you get your CYA down to reasonable levels.

You haven't said if it is a liner pool or gunite. You might want to add that to your sig. Makes a bit of difference on the advice you will get. Also your general location would be a good thing.

 

[JohnN]

Just a suggestion on the R-0013. For the most part, it doesn't go bad, so consider buying the 16 oz bottle. You can get it on Amazon or Amato Industries (amatoind.com) It is much more economical than getting the smaller bottles.