First time at TFP, First Pool, First Problem

Jump to latest Follow Reply
TriangleMan

TriangleMan

Well-known member
May 30, 2021
78
Lake Barrington, IL
Pool Size
25000
Surface
Vinyl
Chlorine
Liquid Chlorine
Hello World!
I'm familiar with pools from being around them all my life, but am the proud new owner of my own first pool, and after maintaining it pretty well for a month and a half, I've run into my first real problem! I've been reading articles on here and perusing the forums, so I think I'm ready to raise the call for help and provide as much info as I can.

I have a 25,000 gallon vinyl liner pool with a heater, automatic chlorinator using trichlor tabs, and Nature 2 mineral cartridge.
Here's how it started and how it's going:

My own test kit, as recommended by TFP, is on order, so what follows is based on pool store analysis:

5/26/2021:
Water looks crystal clear and is highly enjoyable:
Store #1:
FC: 1.13
TC: 1.13
pH: 7.6
TA: 116
CH: 251
CYA: 115
(Also, water temp 90, Iron 0, Copper 0, Phosphates 3993, and TDS 1250)

6/1/2021:
Water is terribly cloudy (can barely even see the bottom of the shallow end 3 feet down)
Over the last couple days I've added about 3 lbs of calcium-hypochlorite and 10 gallons of (10%) sodium hypochlorite to no effect.
Backwashed out about 1000 gallons (2") to start diluting CYA, re-adding from (known high TA) well water, and also getting maybe 0.5" rain
I even got desperate and added 16oz of "clarifier".
The following are the measurements after doing all of the above:
Store #1: Store #2:
FC: 0.23 FC: 0.3
TC: 1.32 TC: 1.9
pH: 7.4 pH: 7.4
TA: 178 TA: 153
CH: 239 CH: 278
CYA: 44 CYA: 46
(Iron 0, copper 0.1, phosphates 3428, TDS 1400)

I'm terribly confused! I figure algae is taking hold because FC is low for the CYA level on 5/26 from what I've read on this site, but from everything I've ever heard CYA doesn't go away, so how is it suddenly 44-46 on 6/1?? There's no way I lost and diluted over 50% of the water. How did that happen? Did it combine with the chlorine I've added and will just come back once FC = TC again? The dramatic drop in CYA also matches what the quick-test strips have been telling me, for what that's worth. I'd really like to understand this mystery so that I can better understand how CYA works.

More importantly, (and possibly related) how do I clear up the cloudiness!
Store #1 says the cloudiness is caused by high alkalinity and phosphates, add 42 lbs of sodium bisulfate (dry acid), 3.25 lbs of 73% calcium-hypochlorite, and 4 gallons of phosphate remover.
Store #2 says the cloudiness is caused by high combined chlorine: add 7 lbs of 73% Calcium Hypochlorite but I'm afraid of what that will do to the calcium level.

My gut feeling: Store #2 is on the right path, but I plan to use liquid chlorine (sodium hypochlorite) instead.

I suspect, based on what I've read about SLAM on here, that it's going to take more than just 1 treatment to fix. What should I do and how much chlorine do I need to stock up on??
Thank you very much for your advice!

Jim
 
Welcome to the forum!
While you are waiting on your test kit, add 5 ppm FC worth of liquid chlorine / plain bleach to your pool each evening with the pump running. This will replenish the FC lost each day to the sun and also inhibit any algae in the water from growing further.
Once you get your test kit, run a full suite of tests and post them here.
I suggest you read ABC's of Pool Water Chemistry.
 
the very best thing you did was found us :)

for your pool use poolmath but here is the amount for 10% liquid chlorine.. 1 gallon 1 quart or 1.3 (128 oz) jugs
 
  • Like
Reactions: Shirker
The answer to the mystery is... pool store testing can't be trusted. You've just experienced two stores with very different test results and very different answers to the same thing, cloudiness. Your own testing will result in accurate results that you can trust. Then you will only put into your pool water exactly what it needs to be balanced and sanitary.
 
As you are discovering, pool store tests are unreliable and inconsistent with not only the results but their recommendations. Once you have your own results from one of the recommended test kits Marty & all will be able to give advice on your next steps. The daily addition of CL will at least keep pool from getting worse until your kit arrives.
 
I hear you about the inaccuracy of the pool store testing. I'll let you know when I get my kit (projected to be delivered this weekend or early next week).
In the meantime, I'm considering shocking the pool with at least 4 gallons of 10% chlorine as suggested by SLAM, and then adding the 1.4 gallons per day as suggested above and by PoolMath as well.

The CYA had been tracking above 100 for a couple of weeks, which had me very worried. All of a sudden after the cloudiness (which I attributed to the ineffectiveness of the free chlorine) it dropped to under 50 out of the blue. Test strips seemed to confirm what the stores were telling me prior to the cloudiness, with CYA colors above 100, and those same test strips now clearly showing a color between 0 and 50 after the cloudiness and my attempts at correcting it...

Just don't understand how CYA went down like that after consistently testing high using multiple (granted inaccurate) methods, and then dropping low as measured by at least 3 (granted inaccurate) sources. Even given the inaccuracy, the consensus would seem to suggest a trend...
 
Last edited:
The CYA test is the one that pool stores mess up more than the others. Your test kit, when it arrives, will tell you the real story. A tip on running the CYA test is to do it in full sunlight with your back to the sun and the tester down at waist level in the shade of your body. Fill the vial to each level starting with 100 and then quickly glance at the sample to see if you can see the dot. Glance and look away, don't stare or you mind will start to play tricks on you. If you see the dot, pour solution to the next line and repeat the process until you no longer see the dot. That is your CYA #. If the dot disappears before even reaching 100 on the tester, you should do a diluted sample with half pool water and half tap water and run the test like normal. Then double the result to get your final CYA number.
 
  • Like
Reactions: TriangleMan
Ok, here's the real story! Courtesy of the Taylor K-2006-C:

FC = 3.6
CC = 0.8
PH = 7.7
TA = 210
CH = 320
CYA = 35

So I assume I should SLAM until I pass the 3 criteria and then only lower TA after that?

Thanks all!
 

Enjoying this content?

Support TFP with a donation.

Give Support
triangleman3 said:
So I assume I should SLAM until I pass the 3 criteria and then only lower TA after that?
Click to expand...
Correct. Lower the pH to 7.2 and use 40 ppm CYA for a SLAM level FC of 16.

Start using 10ml water sample for FC/CC testing. One full scoop of powder and each drop of reagent to clear is 0.5 ppm FC.
 
  • Like
Reactions: TriangleMan
Excellent, thank you! For the one scoop of powder should I level it off or use a heaping mound?

I'll be testing my well water next to see just how bad it is. I suspect I'll be chasing TA for the rest of my life.
 
Keep an eye on your filter pressure and backwash when it rises 25% over clean pressure.
Good luck with SLAM. Remember, the M means to *maintain* the FC at SLAM
level throughout the process. The more you test and adjust, the faster it will go.
 
  • Like
Reactions: TriangleMan
I appreciate it everyone! So now I got overzealous brushing and the brush slipped off the edge of the bench only to have the metal pole whack it and cut a quarter inch slice in the textured liner. Ugh. If not for bad luck I'd have no luck.

No one to blame but myself. Sigh. : (
 
  • Wow
Reactions: Lilypad

Enjoying this content?

Support TFP with a donation.

Give Support
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply