discrepancy on cya between me and pool store

[Blairswim]

We put in a new liner in our 22,000 inground sand filter vinyl lined pool ourselves and it looks great! We filled with city water and it has been 3 weeks. I've been using a HTH test kit that uses drops not a test strip. It only came with 2 CYA tests. I'm in the market for a Taylor kit. So, the city water was super high on alkalinity and low on chlorine. CYA read 0. CA was okay and ph was around 7.8. I added Clorox brand stabilizer from walmart. 22,000 inground pool. So measurements advised basically 2 bottles worth. I added one and though I'd wait a month and see where I was. We've been busy and traveling and the water looks great so I wasn't too worried about it and was planning to fix my alkalinity this week. Ive been using walmart hth hypocal I had to keep it clean and tabs in the filter since we were gone a lot. I had added phosfree spring too due to some bad advice. (i know, i know). I noticed last week my ph was getting high. I rechecked my CYA with my last test and it STILL wasn't very cloudy at the 30 line. *daytime under the awning. So, I go to the pool store for a double check on my levels before i go crazy working on the alkalinity and they are telling me my CYA is 98!!!!!!!!!!!!!!!! I don't even know what to do with this information. I know know know know I did the test right. Few questions: 1. do I just need to order the add on tests and replenish the chemicals/tests im running low on? Is the chemicals/tests in the hth kit inferior -- i thought a phenol red was a phenol red regardless of the label. Im open to ordering the full Taylor kit, I just don't want to be wasteful with my money if it isn't necessary. 2. what the heck on the CYA???????????? I don't even know where to go from here. My drops say I need to add a pinch more. their way says i need to drain. thoughts????

 

[Blairswim]

oh here is my most recent test results. I totally forgot to address. I need to SLAM i think according to what im reading about elevated combined chlorine. Do i fix the alkalinity 1st or do it all at the same time. I feel a little overwhelmed in regards to the order to manage things.

Total Chlorine-- mine 2 store 1.8
Free Chlorine- store 0.8
Combined Chlorine- store 1
Alkalinity- mine 220 store 226
pH - mine 7.8-8 store 8.4
Hardness- mine 330 store 297
CYA- mine <30 store 98
optimizer plus????-- store 27 low

 

[mknauss]

I would not call the HTH test inferior, but by the time you buy refills you will spend near a proper test kit with top of the line Taylor reagents.

Your FC is too low and CC could be indicating something.

I would suggest you add 10 ppm CYA. Use FC based on 40 ppm CYA (assuming what you add is in there), raise FC to 10 ppm, and do a Overnight Chlorine Loss Test

 

[PoolFool.]

IIRC Walmart sells stabilizer in 4 pound jugs.
Pool Math says 4 lbs in a new pool at 22K gallons would be a CYA of 16. So how many ounces of CYA did you add already.
hypocal and chlorine pucks are going to add more CYA with each use. 8 oz of trichlor will add around 2 CYA to your pool, hypocal half that approx. depending on strength.
So I would start with a count of best guess of how much CYA raising chemicals you have used. See if you can get closer to your 30 number than the pool store. The pool store would take a LOT of pucks to get there.
I think a 3 inch trichlor puck is 8 ounces. ???

Use the very bottom of the pool math calculator to find the effects of adding chemicals. I matters what concentration you are using.

Your combined chlorine level also concerns me. I'd do the overnight loss test or just put a shock amount of chlorine in it, but to do that you will need to nail down your CYA level first. Also I don't think you will be able to do a good chlorine loss test at 10 ppm unless you use a FAS-DPD test, or my favorite to precisely dilute your sample with distilled water. I would start with 1 part pool water and 3 parts distilled. Then your reading for chlorine would be 4 times more than indicated.

 

[getreal720]

Step 1 would be to calm down.

You filled with fresh water, and you know you had a CYA of 0 to start from there. You then added one jug of the two that you bought. Simple math will tell you how much CYA is in the pool.

If the 22,000 gallons of water in your pool is accurate, and you haven't used more than a handful of the pucks, we can use math to show (at most) what your CYA levels are. Your jug will tell you how to calculate dosages. It will say something like:

"For every 10,000 gallons of water, add 1 pound of this powder will yield X ppm CYA"

For you this means (since you have 22,000 gallons of water) you will need 2.2 pounds of powder to get that X ppm in your pool.

Just that math alone will tell you how much CYA you have in your pool. Again, if you haven't used more than a handful of pucks, your CYA is not 90+ unless someone is adding it to your pool without you know it.

Don't use pool store tests. The CYA test alone shows how phoney they are. Assuming a CYA of less than 30, you'll be fine using a regular OTO chlorine test for the time being.

Get a better test kit as soon as you can. In the mean time, do not add any more stabilizer or worry about what the pool store has to say. Maintain a FC count of 5-7 (erroring on the side of caution)

Other than not having a confirmed CYA level, the only thing I see "wrong" is your FC is too low.

Adding a gallon and a half of 6% strength regular cleaning bleach will add about 4ppm free chlorine to the pool. That should help give you a good idea of how much bleach you'll need to add daily. Expect at least one gallon per day roughly, to maybe as much as 1.5 or 2.

Remember that using the OTO test kit is normally limited to 5ppm and that is both free and combined chlorine. This is why its a good idea to get a TF-100 or Taylor K2006 when you get the chance. The only test I'd even consider believing from the pool store is the chlorine tests both free and combine chlorines. Those should be "fairly" accurate.

Don't let the pool store talk you into buying anything right away.

 

[Blairswim]

Thanks A TON!!!!!!!!!!!!!!!!!!