Not sure I understand what's happening with pH and TA

[LCSJersey]

Hello again- I'm a new pool owner coming to the end of our first pool season. I have been using my test kit faithfully but struggled with really deciding what my pH was based on color. I needed a new magnet stir thing so wound up back on the website and saw the digital pH tester so I of course grabbed that. I calibrated it as per instructions and double checked it was reading 7 in distilled water (it was) so put it to work.

Based on the color test (I was diluting about 50 percent with distilled water because I read my high FC can make the pH read too high), I thought my pH was 7.5-7.8.... but the digital was giving me 8.3.

So I started adding muriatic acid and I cannot for the life of me get the pH below 8, although I'm dropping my TA.

Yesterday: pH 8.3, TA 50, FC 17.5 (CYA is 200 and CH 200 from a few days ago).

I added 1 gal chlorine and 72 oz 31% muriatic acid.

Today: pH 8.16, TA 50, FC 22.

I do have a waterfall feature that runs for ~ 1 hour a day, on a timer. I was told it should run a little bit every day to keep water from getting stagnant in there, but I know that will also drive the pH up. Should I kill the timer and just run it manually for a few minutes when I test each day?

I would very much appreciate any thoughts.

 

[mknauss]

Wait until your FC is below 10 ppm to test the pH. I know the tester should be able to measure pH at any FC. But I do not trust the tester. Use your reagent and comparison block.

 

[cwswifty]

Did your new tester come with various buffer solutions of a known pH? How do you calibrate it? Just so you know, you can buy buffer solution in the 8 pH range so that you can check your accuracy more closer to the area of interest.

 

[LCSJersey]

Wait until your FC is below 10 ppm to test the pH. I know the tester should be able to measure pH at any FC. But I do not trust the tester. Use your reagent and comparison block.

I bought the tester because I believed it could be trusted regardless of what the FC is. As you can see with my ridiculous CYA, I can't let the the FC get that low. Do you think the color test is still my best bet?

 

[LCSJersey]

Did your new tester come with various buffer solutions of a known pH? How do you calibrate it? Just so you know, you can buy buffer solution in the 8 pH range so that you can check your accuracy more closer to the area of interest.

It came with 3 known buffers and I followed the instructions to calibrate it with those. When I was done, I stuck it in distilled water and it read 7.03 which I was fine with.

 

[mknauss]

With a TA of 50 and a CYA of 200, you have no carbonate alkalinity. The pH cannot be that high.

You need to drain the pool and get the CYA into a reasonable level.

 

[LCSJersey]

With a TA of 50 and a CYA of 200, you have no carbonate alkalinity. The pH cannot be that high.

You need to drain the pool and get the CYA into a reasonable levei

The CYA has been a work in progress all summer. I have been letting out water to the bottom of the skimmer and then adding fresh from the hose, but obviously its very slow going that way.

 

[JamesW]

You really need to get the CYA below 80 ppm.

Did you do a dilution test for the CYA?

 

[LCSJersey]

Yes! Should have specified. I'm diluting.

 

[pjt]

I have been letting out water to the bottom of the skimmer and then adding fresh from the hose

You need to drain ~2/3 of your water and refill. Draining a couple inches at a time isn't practical.

How are you chlorinating?

Not sure I understand what's happening with pH and TA

Your primary focus needs to be draining and refilling to lower your CYA. pH and TA can be sorted out later.

 

[LCSJersey]

The previous owners used the pool company and tabs, which is how I assume it got so high over the years. I am chlorinating with 10% liquid chlorine and the chlorine dispenser has been empty and shut off since we took over mid June.

I know that I need to get rid of 2/3 of the water, but I guess I'm a little unsure about how to drain that much water. My understanding is that my liner will be ruined if I removed that much at one go? And that I can't let the water level drop below the skimmer? I have a valve thingy that I can set to waste, so physically removing the water isn't the problem.

 

[pjt]

I'm a little unsure about how to drain that much water.

Draining - Further Reading

www.troublefreepool.com

 

[LCSJersey]

So I feel like I'm missing something, and that's been my source of confusion this whole summer. That link says drain to waste but stop once you get below the skimmers, but also, it might be ok to go further with the main drain. If I turn off the skimmers once it drops, can I drain more (down to 18" in the shallow end, as per the link) using just the main drain?

 

[mknauss]

Please read the No Drain Exchange portion of the article.

 

[LCSJersey]

First of all, thank you to everyone here who has given me feedback this pool season and answered my questions.

Here is a link to my most recent post. We have since gone on vacation and then had a family emergency that required some travel, so I'm finally home and circling back. I picked up a pump and, I think, everything I need to do a drain-free water exchange, with the goal of getting my CYA down to 50-70 (yes? no SWG here). My question is what the best timing to do the exchange is. I'm in NJ, we have a heater, so in an ideal world, I'd like to keep it open/using it for a few more weeks yet, but I'm also not sure how wacky my water chemistry is about to get (I've never exchanged this much water before), and also what happens chemically when a pool company closes/opens the pool.

Knowing we were going to do a water exchange, when we left for vacation we said screw it and threw tabs in the chlorinator, so here's my current water test:
FC 25.5
pH 7.2 (via my reagents/Taylor kit, not my digital tester)
TA 40
CYA 200 (I haven't bothered to retest since we used tabs/I think i'd have to do even more dilution??)
CH 200


Anyways, never having closed/opened a pool before (we will be paying a pool company to do it), I didn't know what made the most sense. I'm inclined to do the water exchange now (especially because I have no idea WTF my CYA even is, so I don't really know how to chlorinate), but also am maybe worried if I do it, the pool wont be usable for the rest of the season and that the pool company will just dump stuff in anyway that we'll have to un do in the spring.

 

[dereksanders]

What I can say is you’ll want your CYA to be no higher than 60 and that puts at the top end of the range for LC maintenance. Based on your last CYA test you’ll need at least a 75% exchange, and likely more.

The Free Chlorine and Cyanuric Acid Relationship

Managing your cyanuric acid and Free Chlorine levels is key to stabilizing your pool. Learn how these two items affect each other.

www.troublefreepool.com

 

[LCSJersey]

What I can say is you’ll want your CYA to be no higher than 60 and that puts at the top end of the range for LC maintenance. Based on your last CYA test you’ll need at least a 75% exchange, and likely more.

The Free Chlorine and Cyanuric Acid Relationship

Managing your cyanuric acid and Free Chlorine levels is key to stabilizing your pool. Learn how these two items affect each other.

www.troublefreepool.com

Yeah, I'm trying not to be intimidated by the volume of water I'm about to remove. I'm going to time it with a 5 gal bucket to get a better estimate, but I'm not sure if I should expect this to take..... days?

 

[ajw22]

You have gotten this far into the pool season with your CYA 200.

You can limp along for another few weeks keeping your FC in the 20's and enjoy swimming.

No reason to drain your pool before closing. Let the pool company close your pool. Your CYA will degrade some over the winter and get diluted from rain and snow melt.

Plan to open early in spring 2025 and test your CYA level. Then do any draining to get your CYA down around 40 if you are going to chlorinate with liquid chlorine in 2025. Or consider installing a SWG in Spring 2025 and your CYA will likely be perfect and it will save you money over liquid chlorine.

 

[Deb04]

You can tell your pool company what to put, or not put, in your pool. I tell them not to put any chemicals in and I put them in myself the day before they come.