CYA - WHAT TO TRUST

[Oregonpool214]

Hello all....... as I usually do at the beginning of every season, I take my water sample to the pool store JUST TO REMIND myself of how much I’m saving, how happy I am to not have to go in there all the time, and to see if I’m getting numbers anywhere close to what the pool store computer gets. I’m aware that there are calibration issues, and that my at home testing is probably more accurate, but I also always wonder about the potency and reliability of my reagents (I know, I should buy new every year ). Anyway, I’m jsut getting started and slaming the pool right now (after collecting the tadpoles out of it for my 4 year old ——-yes it was THAT SWAMPY). I got a reading on my test of, maybe, CYA 50, but we all know the issues with seeing that dang dot. Pool store got 31. Water samples taken at same time, the bottle to the pool store sat in my car while driving for 30mins.

The Questions:
(1) do you trust pool store cya or your own
(2) what would account for difference?
(3) would turbidity of my current water have anything to do with this test? it doesn’t appear particularly cloudy in jsut my test tube, but does the cya reageant do anything weird to already-cloudy water? I cannot see the bottom, am jsut now being able to clearly see the first 2 steps. I’m on day 2 of slam.

other data I think you can access in my log?
thanks all!!!

 

[DeanP66]

I would trust your test. If you don't feel confident in your CYA test, try doing your test on a sunny day, with your back to the sun and the sample down by your waist in the shadow of your body. Don't stare at the dot. Pour to the first line (100), look away and look back. If you see it, pour to the next line, and so forth. Once you get to the line where you look away and don't see the dot when you look back, you're done. That is your CYA.

Pool store test numbers are all over the place. Just for fun, I had my water tested so I could use their $5 off coupon off of $25 purchase of 2 cases of muriatic acid, and found all kinds of bad numbers when I compared them to my K2006C test results. I kindly let them explain what I needed, smiled, and said thank you very much, I've got some of that at home.

 

[aussieta]

if the water is cloudy it will affect your reading

 

[mguzzy]

Trust your own tests... Don't let the dark side deceive your eyes!

Pool store testing have no standards. They may have a big fancy machine but yikes.. at my LPS they rinse out the test cells with the last persons sample... yikes!

First off, what is the temp of the water when you took your sample. There is indeed an issue with the CYA test if your water is below 70 deg. let it warm to room temp. And hopefully your room is over 70 deg. If you gave your sample a car ride, in a nice warm seat, let it bask in sun, it warmed up before it got to the pool store.

Second.. you can really get two seasons out of the reagents... BUT always be vigilant of funky readings.. a reagent can go south for any reason. There are ways of cross checking them. and a standard is a good way to check.

Third- if you put your water directly from the pool into the CYA test cylinder does it obscure the dot at any level? If so that is REALLY swampy water. I think I would strain it through a gym sock first and then test it. Most gyms socks won't filter out the CYA but it will catch tad poles.

Fourth- If your water is really that swampy.. scoop and brush and scoop and brush. Get as much of that solid material out of the pool as possible to give the filters a fighting chance. And you are going to have to clean your filters often in concert with the chemical SLAM shellacking you are hitting the water with.

AND Fifth -Next fall consider consider formally closing the pool, or if you do a soft close, run the filters minimally and sweep every now and then to keep it from turning into a green zombie. It is really worth a minimal amount of work in the winter to not have to do the SLAM dance in the spring... trust me I know, I been there.

No more will I teach you today... clear your mind and go hover some rocks

 

[Rich807]

Pool store test numbers are all over the place. Just for fun, I had my water tested so I could use their $5 off coupon off of $25 purchase of 2 cases of muriatic acid, and found all kinds of bad numbers when I compared them to my K2006C test results. I kindly let them explain what I needed, smiled, and said thank you very much, I've got some of that at home.

Pretty much My mode / experience as well.

Using most pool stores as a check of ones own testing prowess sounds logical but is faulty practice. Buy a set of calibrated fixed sample water from somewhere like tfttestkits & use those to double check what you’re doing.

 

[ajw22]

Let’s not lose sight that you test the CYA to set your FC levels. That is the use of the CYA test.

We round up the CYA tests.

If the water is cloudy it will affect your reading on the high side. That is fine.

As long as you error on the high side of the CYA test you will be using adequate FC levels. That is all that matters. You do not need to obsess over getting exact CYA levels.

Trust your testing. It is the most accurate and repeatable.

 

[Oregonpool214]

I kindly let them explain what I needed, smiled, and said thank you very much, I've got some of that at home.

Haha I use the SAME verbiage, and then slightly giggle to myself while I calculate how much I would have spent on their recommendations. Thanks for the reminders on how to accurately do cya test!

 

[Oregonpool214]

Trust your own tests... Don't let the dark side deceive your eyes!

Pool store testing have no standards. They may have a big fancy machine but yikes.. at my LPS they rinse out the test cells with the last persons sample... yikes!

First off, what is the temp of the water when you took your sample. There is indeed an issue with the CYA test if your water is below 70 deg. let it warm to room temp. And hopefully your room is over 70 deg. If you gave your sample a car ride, in a nice warm seat, let it bask in sun, it warmed up before it got to the pool store.

Second.. you can really get two seasons out of the reagents... BUT always be vigilant of funky readings.. a reagent can go south for any reason. There are ways of cross checking them. and a standard is a good way to check.

Third- if you put your water directly from the pool into the CYA test cylinder does it obscure the dot at any level? If so that is REALLY swampy water. I think I would strain it through a gym sock first and then test it. Most gyms socks won't filter out the CYA but it will catch tad poles.

Fourth- If your water is really that swampy.. scoop and brush and scoop and brush. Get as much of that solid material out of the pool as possible to give the filters a fighting chance. And you are going to have to clean your filters often in concert with the chemical SLAM shellacking you are hitting the water with.

AND Fifth -Next fall consider consider formally closing the pool, or if you do a soft close, run the filters minimally and sweep every now and then to keep it from turning into a green zombie. It is really worth a minimal amount of work in the winter to not have to do the SLAM dance in the spring... trust me I know, I been there.

No more will I teach you today... clear your mind and go hover some rocks

Thank you for all of that! no, my dot isn’t obscured from just the regular pool water.... that’s a good way to check, though, thank you. I’m able to see my third step down today, so that’s exciting! I started the process by trying to get the most organic matter out of the pool before adding any chlorine, and I see just the occasional leaf blow up from the deep end at this point.

 

[Oregonpool214]

here she be this evening - I can see the 3rd step down!

 

[wireform]

Well you have a little while yet to go. Keep the slam up several times a day including brushing twice daily.