Rapid pH increase with SWCG

flippinGeo

Bronze Supporter
Oct 8, 2016
81
Maryland
Ok. New tests in. So it seems there may definitely be a correlation between my plaster and these whacky numbers. Understanding that I’m still within the margin of measurement error… I did a full brush last night with my new nylon brush. And today my CH returned 20ppm higher. No chemicals were added other than MA (1gal).
 
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JamesW

TFP Expert
Mar 2, 2011
28,256
Do you have visible scale?

For all intensive porpoises, it seems to be narrowed down to plaster or scale, but the amount that must be dissolving is way more than what seems possible.
 
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flippinGeo

Bronze Supporter
Oct 8, 2016
81
Maryland
Do you have visible scale?

For all intensive porpoises, it seems to be narrowed down to plaster or scale, but the amount that must be dissolving is way more than what seems possible.
There is visible scale in certain locations near the water line for sure. There’s a love seat section that doesn’t get great water flow, which is where most of the scale forms. I wouldnt think it would be enough to impact chemistry, but I can’t rule out anything.
 
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JamesW

TFP Expert
Mar 2, 2011
28,256
I suppose that we can consider it to be one of the deep unsolved mysteries of the universe.

If you could weigh the plaster on a daily basis, we could see if the weight was changing, but that seems impractical.

For now, It seems like watching the chemistry is the best we can do.
 
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JamesW

TFP Expert
Mar 2, 2011
28,256
You might have calcium hydroxide scale if you have ever added Borax and calcium chloride on the same day.

Calcium hydroxide will dissolve easier than calcium carbonate.

If it is calcium hydroxide, the problem should eventually end when the scale all dissolves.

I would try to keep the CSI at 0.0 and brush at least 1 time per week with a nylon brush.

Check the TA, pH and calcium before and after brushing to see if they go up.
 

generessler

Active member
Dec 13, 2020
40
Chapel Hill, North Carolina
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
He did say boric acid (not borax), which I've read slightly lowers pH. No experience, though.
 

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JamesW

TFP Expert
Mar 2, 2011
28,256
The calcium has gone from about 430 to 520, which would require about 17 ppm of calcium chloride.

However, none has been added.

The plaster or scale hypothesis seems unlikely, but there does not seem to be any other explanation.
 

aussieta

Gold Supporter
TFP Guide
looking at your pool logs for the last month, ignoring 1st 2 readings which seem odd
without any additions
ch goes 490, 490, 490, 480, 480, 480, 470, 470, 470, 500, 490, 500, 520
goes up and down like a yo-yo, but averages out to 486, call it 490
if we throw out the last 520, they are all within testing errors
must be a test interference of some kind
 

flippinGeo

Bronze Supporter
Oct 8, 2016
81
Maryland
You might have calcium hydroxide scale if you have ever added Borax and calcium chloride on the same day.

Calcium hydroxide will dissolve easier than calcium carbonate.

If it is calcium hydroxide, the problem should eventually end when the scale all dissolves.

I would try to keep the CSI at 0.0 and brush at least 1 time per week with a nylon brush.

Check the TA, pH and calcium before and after brushing to see if they go up.
I did add borax. At or about 40 ppm now of borates. But I only added acid in that time frame to counter the borax dosage. This was at the end of Aug. Now I did add CaCl a month prior on July 29th.
To clarify I added the borax in an attempt to improve my pH stability, but of course it didn’t work and now I have to use so much more MA to lower pH. FML
 
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flippinGeo

Bronze Supporter
Oct 8, 2016
81
Maryland
And to pile on. Now my water feels sticky! I almost didn’t post this because it sounded so stupid. But it literally made my arm and test tubes have a feeling of a wax cucumber. That is the only way to describe it. Like my fingers won’t slide across a surface wet with pool water, there is additional friction like it’s skipping.

looking around here it seems like it could be due to the high pH for extended times. So do I drop the pH and let it work on this scale and mineral deposits. I’m about 2 weeks from closing. We haven’t swam in over a month. Thinking this thing needs an acid wash at the start of next season.
 

flippinGeo

Bronze Supporter
Oct 8, 2016
81
Maryland
Any thoughts on my sticky water? I assume it’s related, either by cause or effect.

CH continues to rise. pH jumped almost 1 point in just 3 days. This is insane!

If this is the plaster dissolving then I’m screwed because we had it replastered 3 years ago and I’m sure there’s no warranty coverage as I’m sure the liability will fall to me accusing us of badly balanced water.
 

flippinGeo

Bronze Supporter
Oct 8, 2016
81
Maryland
Where's your salinity at? Thinking maybe barely getting by the minimum and it's not that silky smooth feeling anymore. Pool water in a non SWCG pool with very low salinity has the catchy feeling you complain of.
So I’ll test salt tomorrow but I’m pretty sure it’s at 3600-3800, hasn’t rained much since my last test. I’m familiar with the non salt feel you speak of. This is not it. It’s like actually sticky. My fingers stick to the test tubes until I rinse them with my tap water. It’s the craziest thing.
 

flippinGeo

Bronze Supporter
Oct 8, 2016
81
Maryland
Honestly, I am totally stumped.

I have never seen anything like this and I have no idea what is happening.

:unsure::unsure::unsure::unsure::unsure::unsure::unsure::unsure::unsure::unsure:
I hate to close it in this condition. But I won’t have time to drain, acid wash, then fill before closing time. Something to look forward to next spring I guess 🙄.

Certainly seems like I should get new fill and start over.
I definitely think having to dump a gallon of acid in this thing every 2-3 days is not helping anything. Certainly not my wallet or sanity.
 

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