How to measure CYA that is under 30ppm?

[Baker25]

Hey all,

First thank you all for contributing so much information on this site. Thankfully I found this site before I paid an absurd amount of money for chemicals I did not need.

So here is the deal. I learned from reading here that using those chlorine pucks add CYA which I don't want. So I took them out, and yesterday morning around 10am I added an amount of bleach that I got from the pool calculator. After about 30 min I was at 3ppm ish. Now I know there was a time that there was no chlorine in the pool and so I am going to do the SLAM method in the coming days but I want to get my CYA in check. Last night around 7pm I checked and I had no FC. Added another 66ish oz of bleach. This AM I was at 1ppm. I tested my CYA yesterday but I did it inside but I filled that tube all the way up and could easily see the black dot. I will retest today outside, back to the sun, test at my waist like I found on here. So I believe my CYA is less than 30. I believe two things are happening, one is that I have growth which is eliminating my FC and I have low CYA which is allowing my FC to burn off. So, when I retest today doing it the right way and it still shows under 30ppm, how do I determine where it's exactly at so I know how much stabilizer I need to put in? Should I do two separate treatments so I don't add to much? I bought the liquid instant pool conditioner. I know it's more expensive but I have more money than time right now. I have a 12700 gallon above ground w/ liner and live in northern Illinois. Once I get my CYA in check, then I can do the SLAM method that I read about on here. Would you all still suggest 50ppm CYA or something different for my region? Any tips on introducing the liquid conditioner into my pool for the best results? ​

 

[Texas Splash]

So, when I retest today doing it the right way and it still shows under 30ppm, how do I determine where it's exactly at so I know how much stabilizer I need to put in?

Since you know there must be "some" CYA in the water, the best way now is to simply add stabilizer/conditioner in stages - perhaps using PoolMath to add in increments of 10ppm. Add enough to increase by 10ppm, if it's not high enough, add more. The liquid conditioner you bought should show-up quite quickly to where you can get it adjusted in a matter of hours. SLAM with your CYA at 30 is possible to use less bleach. Once you pass the 3 SLAM criteria, you could increase CYA to 40 and see how that works.

By the way........ WELCOME TO TFP!

 

[Poolzzz]

Sounds like you're using 8% bleach?

How many pucks have you used and what size are they? It's possible to calculate how much cya they added using Pool Math.

Since you are losing fc overnight and you've gone for periods with no chlorine I'd raise fc to SLAM level (12ppm) and hold it there. You have algae now so no sense waiting and let the algae take off. Adding 10ppm of cya plus what you already have is plenty to start the slam. You'll be at cya=30 soon enough anyway.

 

[Baker25]

Since you know there must be "some" CYA in the water, the best way now is to simply add stabilizer/conditioner in stages - perhaps using PoolMath to add in increments of 10ppm. Add enough to increase by 10ppm, if it's not high enough, add more. The liquid conditioner you bought should show-up quite quickly to where you can get it adjusted in a matter of hours. SLAM with your CYA at 30 is possible to use less bleach. Once you pass the 3 SLAM criteria, you could increase CYA to 40 and see how that works.

By the way........ WELCOME TO TFP!

See, this is why I asked. The answer to just try and do 10ppm increments is so simple and easy. Thank you!

Sounds like you're using 8% bleach?

How many pucks have you used and what size are they? It's possible to calculate how much cya they added using Pool Math.

Since you are losing fc overnight and you've gone for periods with no chlorine I'd raise fc to SLAM level (12ppm) and hold it there. You have algae now so no sense waiting and let the algae take off. Adding 10ppm of cya plus what you already have is plenty to start the slam. You'll be at cya=30 soon enough anyway.

So this pool was installed 9 days ago. Never owned a pool before that. In that time, I had 2 pucks in a floater. Then I ended up buying a chlorinator and installed that 2 day ago. I put 4 pucks in. I took the pucks out yesterday morning right after I put the bleach in. I am using 6% bleach for now. I can't start the SLAM until Wednesday morning. I work tomorrow all day and my wife works at night. However Wednesday morning I start a 7 day vacation so I will knock it out then.

Another question, lets say I get my CYA to 40 and begin the SLAM. My target shock according to the chart is 16ppm. How far below that can it go before its to late? Like I get it to 16 right before bed, and then I can't check it all night. Trying to figure out what the acceptable range is. Thanks again all!

 

[lightmaster]

Obviously you can't add more bleach while you sleep, but without the sun hitting it at night, the FC should be used up a bit slower anyways. Just check your FC every couple of hours while your awake and bring it back up to SLAM level whenever it's low. The more diligent you are about raising it back up to SLAM level, the better your slam will be.

Don't worry about testing your CCs until you notice little to no FC loss overnight. There's no point wasting the reagent cuz you know the CC will be high anyway.

- - - Updated - - -

Also, make sure to brush your pool several times a day, and check for signs of algae behind the weir on your skimmer, behind any lights, under the rungs on any ladders, etc. Any place where circulation will be low, algae can hide and survive.

 

[Baker25]

Obviously you can't add more bleach while you sleep, but without the sun hitting it at night, the FC should be used up a bit slower anyways. Just check your FC every couple of hours while your awake and bring it back up to SLAM level whenever it's low. The more diligent you are about raising it back up to SLAM level, the better your slam will be.

Don't worry about testing your CCs until you notice little to no FC loss overnight. There's no point wasting the reagent cuz you know the CC will be high anyway.

- - - Updated - - -

Also, make sure to brush your pool several times a day, and check for signs of algae behind the weir on your skimmer, behind any lights, under the rungs on any ladders, etc. Any place where circulation will be low, algae can hide and survive.

So I can be in the pool with the FC is at the 16ppm? Or are you talking doing the cleaning from outside the pool? I hate cleaning from outside the pool so I am hoping I can enter the pool for brief periods of time while keeping it at shock level.

 

[Poolzzz]

Since you have algae suggest raising your fc to slam level now and as often as you can test between now and when you formally start the slam. Every bit helps.

The slam levels aren't critical it still works if a few points low. ..just takes longer. Read the slam procedure and follow it best you can.

You can safely swim in the pool at slam levels so no problem entering it to brush.

 

[Baker25]

Since you have algae suggest raising your fc to slam level now and as often as you can test between now and when you formally start the slam. Every bit helps.

The slam levels aren't critical it still works if a few points low. ..just takes longer. Read the slam procedure and follow it best you can.

You can safely swim in the pool at slam levels so no problem entering it to brush.

Makes sense. So I did the CYA test when I got home. The black dot was perfectly clear. I did not see any form of cloudiness after mixing for 30 seconds and adding it to the smaller compareter. So I added approx 66oz of instant conditioner. Which from 0ppm CYA is about 15ppm CYA for my size pool. So I should SLAM to the shock level for 15ppm CYA correct? And as I inch up my CYA then inch up my shock level? Last question, how long should I wait after adding the instant conditioner before I add any cholorine? The sun is starting to go down so I am not going to add any more conditioner until I can retest it. Thanks again all!

 

[lightmaster]

Makes sense. So I did the CYA test when I got home. The black dot was perfectly clear. I did not see any form of cloudiness after mixing for 30 seconds and adding it to the smaller compareter. So I added approx 66oz of instant conditioner. Which from 0ppm CYA is about 15ppm CYA for my size pool. So I should SLAM to the shock level for 15ppm CYA correct? And as I inch up my CYA then inch up my shock level? Last question, how long should I wait after adding the instant conditioner before I add any cholorine? The sun is starting to go down so I am not going to add any more conditioner until I can retest it. Thanks again all!

You can and should add chlorine as soon as you add the CYA.

The CYA test is not a linear scale, so just because the dot may disappear halfway between a set of numbers, say 20 and 30, doesn't mean it's 25. Always round up. So if you added enough to get to 15ppm, round up to 20ppm and slam at the shock level for 20ppm. When you add more CYA enter 20 for now and 30 for target, and add however much it says. The CYA test won't always show anything under 20ppm, so you could he at 15ppm and the test my not have changed. Or if you were at 15ppm already (test falsely showed 0ppm since you were below it's threshold) the next test result would show 30ppm.

So start your SLAM assuming 20ppm, test CYA again tomorrow and see what it says. (I only say test CYA tomorrow since you're using liquid CYA. Granular CYA takes much longer to show on a test and you'd have to wait a couple days to get an accurate result for the new level)


And yes, you can safely get in the pool as long as the FC level isn't above it's shock level, assuming you can see the bottom.