CYA still very low after startup

[Strop]

Hi,

Filled the pool a week ago and put 5 lbs of Stabilizer into 2 socks starting on 5/26 (as recommended by the Forum). 99% of the stabilizer powder has dissolved but CYA is still very low. Test results as of last night. The CYA number is an estimate since the last number on the measuring tube is 20.

FC = 0.5 (added 45 oz of bleach per the app)
CC = 0
pH = 8.0 (added 38 oz acid per the app 30 min after the bleach)
TA = 120
CH = 200
CYA = 10 (or less)

Should I put another 5 lbs of Stabilizer in the socks?

I'm new to adding Stabilizer...this is my first drain and refill. I didn't expect the CYA to be this low after already adding 5 lbs. Chlorine is burning off fast. I've already used a gallon of bleach since last Saturday.

Thanks,


Strop

 

[jblizzle]

What was your cya Target in PoolMath that told you to add 5 lb?

 

[jblizzle]

Also only adding a gallon of bleach in 5 days is very low. Where they pull that size you likely need to be adding at least a half gallon every day

 

[Strop]

Hi,

The target for Cyanuric Acid is 40. And, the recommended add is 4 lbs and 6 oz. Should I add as recommended?

Thanks,


Strop

 

[mknauss]

What stabilizer did you use? 5 lbs would have give you just over 30ppm CYA. You should be able to test that.

 

[jblizzle]

5 pounds into 17,500 gallons already added 34ppm of CYA. That is just a chemistry fact. So, unless you drained a bunch of water after adding the stabilizer, you should already be above 30ppm.

If you add another 4.5 pounds, that will add another 30ppm ... so you may overshoot if this is just a testing error.

 

[Strop]

The stabilizer brand is "ALL-CLEAR" and comes in a 5 lb square- shaped container.

 

[mknauss]

Do you have the container? Does it show nearly 100% Cyanuric Acid on it as ingredients?

 

[Strop]

Yes. Maybe my test kit is off? I have the TF-100. I can't remember when I last purchased an R-0013 refill bottle. Maybe 6 or 8 months ago. Does R-0013 go bad?

 

[mknauss]

R-0013 normally does not go bad. It is the most stable of all the reagents.

 

[Strop]

I don't have the container but I'm fairly sure it said 100% cyanuric acid.

 

[mknauss]

I tried to search for it and only came up with Dichlor. If it was Dichlor, it would have added 17 ppm of CYA.

 

[Strop]

How critical are the level marks (top and bottom of the sticker) on the CYA mixing bottle in the TF-100 kit? I find when adding pool water and R-0013 to the mixing bottle the fluid "curves" quite a bit. I remember back from high school chemistry days the level of fluid in a bottle or container should be taken at the very bottom of the curve of the fluid. So, maybe I'm adding too much pool water and not enough R-0013? Hence my CYA reading is artificially low.

 

[mknauss]

I have to be careful with that too. It is called the meniscus. You want the bottom of it at the top of the label. Be sure the bottle is set on a level surface.

But I doubt that will make as big a difference as you are showing.

 

[Strop]

There is an image of All-Clear stabilizer on swimmingpoolproducts.yolasite.com/swimming-pool-products.php. Just scroll way down the page.

 

[mknauss]

OK -- well -- the CYA is in the pool. Try brushing, really mixing up your water and try the test tomorrow.

Or, just add another 20 ppm worth of CYA and see what happens. You want about 50 ppm in the water anyway.

 

[Strop]

I've read CYA takes a long time to show up in test results but maybe that is if Stabilizer was added in bulk at the skimmer.

- - - Updated - - -

Ok, I'll brush the walls and bottom and try and stir things up. Thanks for the help!

 

[mknauss]

The method of dumping the stabilizer in the skimmer does take longer for it to show up. And normally it does not all show up as some drops into the no-flow areas of the filter and never dissolves. I saw that when my pool builder did just that and it would never test and when I cleaned my filter I found a couple cups of granules in the bottom of the filter.