Rapid pH increase with SWCG

flippinGeo

Bronze Supporter
Oct 8, 2016
92
Maryland
Guys, I'm losing my mind with this pool. I've scoured all the threads on this topic here and in other forums. I've tried every "remedy" I could find, and yet, here I am, dumping gallons of acid in at a time only to come back a few days later to pH > 8.0. I've always felt I was very diligent with my pool, chems, testing, and cleaning. But I'm seriously contemplating filling this sucker in.

OK. So this spring I converted to SWCG from trichlor tabs. I know SWCG create pH rise, but this is ridiculous. I already suffer with respiratory issues and handling Muriatic Acid in such volumes so often is actually not good for me. I ask that any of you take a look at my PoolMath Logs (PoolMath Logs). Last year, before SWCG, I was able to maintain pH incredibly, only occasionally adding chems to raise/lower to my desired pH (which was 7.6). However, you can see this year it's been an incredible struggle that I cannot seem to win. So far this season I've added almost 1,200 oz of MAcid, not including the 404 oz added as part of my borate attempt (below). Pool store loves me!

If you look at the logs starting 9/6 - You see I had pH of 8.4, added 1 gal of MA to bring down to pH of 7.5. 24 hours later I'm up to 7.8, and 24 hours after that 8.3.

What I've tried:
  1. Reduced SWCG/pump run time - I used to run my intelliflo pump 24/7. I quickly realized this was too much chlorine generation. I now only run 12 hours a day with my IC40 at the 4% output. My chlorine seems to be stable with that setting. Any less and I can't maintain a target of 4-6 FC.
  2. Lower TA to 60 - Per numerous suggestions to lower TA to 60 I performed a series of acid additions and aeration to bring the TA to 60. However, it would never hold. And the pH was no more stable after the TA drop, then before. As you can see, my pool seems to want to be at 70 TA. Except for this past week I was away on vacation and the TA pushed up to 120. I just added dose 1 of MA to bring my pH down to 7-7.2 so I can aerate.
    1. Result - pH rises rapidly despite the lower TA.
  3. Borates - Lastly, I tried boric acid. I'm now sitting at borates of 38ppm, but nothing has changed with the pH. It rises just as fast now as before. Only now I have to add so much more MAcid to lower the pH. Costing me more in chemicals now than before.
This just seems excessive. I see folks here stating they have to add a bit of acid every few weeks, but nothing of the likes I'm experiencing. I'm at a loss and open to any and all suggestions here. This has been a miserable pool season for me, which is the opposite of what I expected with the SWCG conversion. I'm truly at a loss.

Thank you in advance for any and all comments, questions, and support.

Pool details
  • 20,000 plaster roman style
  • Intelliflo (running 2000rpm 12 hours a day 8A-8P)
  • IC40 SWCG (running at 4%)
  • QuadDE filter (100sqft)
 

flippinGeo

Bronze Supporter
Oct 8, 2016
92
Maryland
What is the pH and TA of your fill water?

Do you have an autofill on the pool?
No autofill. Fill water can be seen on May 20. I had a full drain and fill with pool truck water. 6.8 pH TA 70. We get enough rain and humidity this season that I actually haven’t had to add no more than 1000 gallons (est). Our well water is extremely acidic to to road salts and clay soils.
 

Charlie Bezzina

Well-known member
Jul 10, 2021
175
Sydney Australia
Pool Size
38000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-9)
Flipingino, sorry to hear you have respiratory issues.

Something to consider once you better understand the effects of adding chemicals to your pool might be an acid doser.

I have an automatic acid doser and I have to say it works really well. My pH is rock solid and I don't need to touch any hydrochloric acid untill the 15 litre drum gets low (many months for my pool)

Also, the lower strength acid should fume less however it is obviously less economical. But as they say, how much money are your lungs worth?
 

Bperry

Gold Supporter
Aug 20, 2020
2,233
Knoxville, TN
Pool Size
27000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-60
It looks like the borax was a big part of the recent pH increase, but even a few months ago, you were dosing the pH from 8 down to 7.2/7.4. You should probably not try to get the pH so low. Let it stay at 7.6-7.8 and it’ll be more stable.
 

flippinGeo

Bronze Supporter
Oct 8, 2016
92
Maryland
all of the borax you added was raising your ta and ph
the amount of borax and baking soda almost balances out the amount of acid you added
if you had added nothing you may have needed 50oz acid for the month
try not to lower your ph so much
if above ph 8 add acid targeting 7.8
Thank you Aussieta.

So the 2 large borax doses were to build up my borates. This was recommended in another post of someone struggling with pH rise and other benefits. The borax was added at the same time as the large acid doses to increase borates without impacting pH. I did have to add acid in between the borax doses to get my pH back to target.

I know without the borates I would have to add less acid to bring my pH down, but the point of the borates was to help eliminate the rapid rise. Obviously now I wished I hadn't added borates because I'm seeing no benefit and now I have to use so much more acid.

The lowering of the pH to 7.2 is 2 fold. 1 to get my TA down, and 2 to keep from having to add acid so often. I hate the swings, but if I bring my pH down to 7.6-7.8 (target) in the morning, by the evening it will already be at or above 8.0. So now I'm dosing at least 2 times a day.
 

flippinGeo

Bronze Supporter
Oct 8, 2016
92
Maryland
Flipingino, sorry to hear you have respiratory issues.

Something to consider once you better understand the effects of adding chemicals to your pool might be an acid doser.

I have an automatic acid doser and I have to say it works really well. My pH is rock solid and I don't need to touch any hydrochloric acid untill the 15 litre drum gets low (many months for my pool)

Also, the lower strength acid should fume less however it is obviously less economical. But as they say, how much money are your lungs worth?
I have thought about it. But, as you stated, until I can get this pH more stable I'd be filling the reservoir probably on a 3-4 day basis. haha.
 

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flippinGeo

Bronze Supporter
Oct 8, 2016
92
Maryland
It looks like the borax was a big part of the recent pH increase, but even a few months ago, you were dosing the pH from 8 down to 7.2/7.4. You should probably not try to get the pH so low. Let it stay at 7.6-7.8 and it’ll be more stable.
I guess that's where I'm having issues. If I bring my pH down to ideal (7.6 - 7.8), by the evening it is back up to 8.0+ so now I'm dosing multiple times a day.
 

flippinGeo

Bronze Supporter
Oct 8, 2016
92
Maryland
I just tested again and it seems like my 8.4 interpretation from last night was short. Added 1gal of MA last night and still rendering above 8. Just added 100 more oz and will test again in about an hour. Jeez. My pool store will only sell me 4 gallons at a time. At this rate I’ll be going to the pool store 2 times a week.

Following up on the question about my fill water. I test out well water and pH was way lower than the gauge. Bright yellow urine color. Guessing low 6s. TA was 30. Needless to say it’s acidic and not contributing to this rise. Not to mention I’ve only had to add water 2 times this season and very little each time.
 

Tcadwall0

Gold Supporter
May 19, 2021
206
Charlotte, NC
Pool Size
12900
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-20
I may have missed it, but do you have anything that is aerating your pool? spill-overs, waterfalls, bubblers? are your returns breaking the water surface hard?
 

flippinGeo

Bronze Supporter
Oct 8, 2016
92
Maryland
No water features, and no breaking of the surface. I keep the jets down and running 2000 rpm I almost have the walk towards the pump to make sure it's on as the surface is very still.

A few other descriptive details.
  1. Pool was replastered, but this was now 3 years ago so I'd find it hard to believe it is playing a role.
  2. I'm using a Taylor complete test kit. I purchase a new one every year and the chems are good and I store them in a cool dark place at all times.
  3. Pool gets full sun all day.

Thank you to everyone so far for your input. I'm a damsel in distress.
 

JamesW

TFP Expert
Mar 2, 2011
32,428
On September 10, your TA was 65 and then on September 19, it was at 120.

What was added to increase the TA?

Whatever is increasing the TA is causing the problem.

TA does not rise on its own.

Something has to be added to increase the TA.
 
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flippinGeo

Bronze Supporter
Oct 8, 2016
92
Maryland
On September 10, your TA was 65 and then on September 19, it was at 120.

What was added to increase the TA?

Whatever is increasing the TA is causing the problem.

TA does not rise on its own.

Something has to be added to increase the TA.
JamesW I'm baffled by this as well. So on the 10th my TA was down to 55 so I added 23oz of Baking Soda to bring it up some. 8 hours later my TA was up to 65. My TA is consistently 70-80. It has never risen this high.

However, I left for Myrtle Beach on the 11th. There were no chemicals being added from the 11th through yesterday (19th). I'm not clear on how the TA would have climbed so much other than my pH being astronomically high since I wasn't able to dose acid while away.
 

JamesW

TFP Expert
Mar 2, 2011
32,428
The TA cannot go up unless something is added.

If it is not coming from the fill water, then it seems like someone is adding something.

If you have really bad calcium carbonate scale, the scale can dissolve and raise the TA and pH, but it would require about 12.84 lbs. of calcium carbonate scale or plaster to dissolve and that is not likely.
 

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