Getting concerned with CYA level

[fireman00]

Hey all! DW and I have been having good luck with our above ground beauty since it was installed last spring but... I"m concerned with the CYA level. When I opened the pool this spring I shocked it with a couple of pounds of powdered shock and some Calcium as per the pool store. I also added 8 oz of algaecide in mid-June on 2 different weekends but nothing since June 14th.

The CYA level has been slooooowly rising over the last month and a half.

In late June I used one puck each week for 2 weekends when we were away but I don't use them regularly.

I add 1.5 qts of liquid chlorine every other night.

Pool is spotless and clear.

Is there anything else that would cause CYA to keep rising?

Any help is much appreciated!

Numbers to date are in the linked file... from my neighborhood pool store, Town and Country Swimming Pools in Phillipsburg, NJ. Family owned and operated for more than 50 years.

and the pool

 

[jblizzle]

The biggest reason the CYA may appear to be rising is that you are still trusting a pool store to do the test.

It can not rise if you are not using any dichlor or trichlor or adding any stabilizer.

 

[Bama Rambler]

Pool stores are really bad at getting the CYA test right. Get a good test kit and you'll have good numbers to go by.

Also, there's no need for CH in a vinyl pool.

 

[jblizzle]

And your FC is too low for a CYA of 50ppm ... so your pool is a ticking time bomb. It should NEVER be below 4ppm: pool-school/chlorine_cya_chart_shock

 

[Isaac-1]

Testing inaccuracy on the CYA test is the likely culprit, the problem is the best common test for CYA is a turbidity test, and to get the best results from the test it needs to be read under the correct lighting condition where is either Outdoors in bright sunlight with the sun to your back or with a VERY expensive daylight simulator deivce, trying to read the CYA test indoors is just asking for error to be introduced into the results.

Ike

p.s. even under ideal conditions you should expect about a 10 ppm error range on the CYA test

 

[duraleigh]

Maybe I am missing something but I don't see an issue at all.

Overall, there is no CYA rise to speak of, at least within the accuracy of the test (plus or minus 10 ppm). That coupled with the consistency of all test results over a period of time and (reading between the lines a bit) OP seems very happy with this pool store's testing (they are very consistent).

Fireman00, what I do see is the FC stays chronically way too low for a CYA of 50 or so. You should keep your FC up around 4-6 ppm to be really safe.

I have a feeling, observing your meticulous record keeping, you are also meticulous about your FC additions, but you are really on the edge....I would bring it up.

What has consistently been trending upward is your CH. You are nowhere near being excessive but it suggests your fill water is the source for the increasing CH and, in time, it may start to get a bit too high (400+)

To answer your question, CYA only rises if you put it in your pool, but I think you know that. I just don't see it trending up overall unless I am completely misinterpreting your spreadsheet.

PS - do you really go to the Pool Store that often?

 

[fireman00]

Maybe I am missing something but I don't see an issue at all.

Overall, there is no CYA rise to speak of, at least within the accuracy of the test (plus or minus 10 ppm). That coupled with the consistency of all test results over a period of time and (reading between the lines a bit) OP seems very happy with this pool store's testing (they are very consistent).

Fireman00, what I do see is the FC stays chronically way too low for a CYA of 50 or so. You should keep your FC up around 4-6 ppm to be really safe.

I have a feeling, observing your meticulous record keeping, you are also meticulous about your FC additions, but you are really on the edge....I would bring it up.

What has consistently been trending upward is your CH. You are nowhere near being excessive but it suggests your fill water is the source for the increasing CH and, in time, it may start to get a bit too high (400+)

To answer your question, CYA only rises if you put it in your pool, but I think you know that. I just don't see it trending up overall unless I am completely misinterpreting your spreadsheet.

PS - do you really go to the Pool Store that often?

Pool store is about 2 miles away! Great family who runs the place. They answered a lot of my questions about AG pools, permits/ build times/ sizes/ depth/ liners/ fences/ etc while DW and I went back and forth over IG vs AG for 2 years.

and yes, our water is extremely hard so that number increasing isn't a surprise and I'm keeping an eye on it.

Good to hear of the +/- 10 when it comes to CYA testing. I'll pump up the CH a bit to try and get more in line with 3 to 4 for FC.

Thanks for the advise all!

 

[jblizzle]

That is not what we said. We said you have to keep the FC > 4ppm at all times. Thus should likely be raising it to 6-7ppm every day so it does not drop below 4ppm.

{And CH here means Calcium Hardness}

 

[duraleigh]

I almost forgot, your pool water looks terrific!

 

[fireman00]

I almost forgot, your pool water looks terrific!

Thanks! And with your tips it'll stay that way. :-D