Another new plaster, sky high pH thread

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B

Bjohn

Gold Supporter
Aug 1, 2021
63
Central Florida
Pool Size
9000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
We finished our build earlier this month and filled on 4/4. I took over the pool last week and started testing using a TF Pro salt kit yesterday. Results from tonight's test are below. The pool has been crystal clear since it was filled.

pH was off the scale (bright fuchsia) both times I tested with the TF Pro as well as the AquaChek test strips provided by the PB. I checked pool math and started by adding a quart of muriatic acid. Let that circulate for a while, restested and added another quart. TA went from 100 to 70 without any noticeable change to pH.

I retested tonight and the pH is still really high, should I keep adding acid despite the quicker drop in TA? I find the daily Cl and pH test to be the hardest to gauge so far given the subjectiveness and variation from ambient lighting. Still there's no mistaking how far off the pH was

Side notes:

I've noticed what appears to be scale (first pool, very new to this) when cleaning the skimmer basket. There's a rough, salt like deposit on the basket. Anything to worry about yet?

PB acknowledged that they went a little heavy on the salt by accident. Chlorinator reads 3650, TF Pro was much higher at 4400.

TIA!

==========================================
JB
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Build Type: Plaster
Volume: 9000 gallons
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Latest Test Result Summary:
FC: 2.0 (2 hours ago)
CC: 0.0 (2 hours ago)
pH: 8.4 (2 hours ago)
TA: 70 (2 hours ago)
CH: 325 (2 hours ago)
CYA: 45 (2 hours ago)
SALT: 4400 (2 hours ago)
==========================================
 
If the plaster is that new, there should not have been salt added yet. Should wait 30 days before adding salt.

TA of 70 should limit pH rise. In fact, if you have a pH of 8.4, that is about as high as it can get with that TA.

Keep adding acid in small amounts and testing. The pH should get into the 7's very soon.

Your FC is well below minimum for your CYA. Be careful.
 
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CYA always rounds up to the next 10. The scale is logarithmic and not linear so halfway isn't 45 like we want it to be.

At that point, only fill to the 10s. There's no need to struggle to figure out 41 to 49 if they all round to 50 anyway. (Etc etc)
 
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Most recent results are below. I just ran to the pool store and they checked with their Taylor kit. Results were pretty close, so that gave me some confidence in my readings.

Pool store had CYA at 40 and salt at 4200. Everything else was the same.

I plan to add more acid and stabilizer. Any other recommendations?

==========================================
JB
------------------------------------------
Build Type: Plaster
Volume: 9000 gallons
------------------------------------------
Latest Test Result Summary:
FC: 2.0 (3 days ago)
CC: 0.0 (3 days ago)
pH: 8.4 (3 days ago)
TA: 70 (3 days ago)
CH: 375 (3 days ago)
CYA: 30 (3 days ago)
SALT: 4400 (3 days ago)
=======================================
 
I would raise your FC to match your CYA. I wouldn't run at minimum, until you learn your pool, I would run at the high end of target FC for your CYA.

Always follow this...Link-->FC/CYA Levels
 
PoolStored said:
I would raise your FC to match your CYA. I wouldn't run at minimum, until you learn your pool, I would run at the high end of target FC for your CYA.

Always follow this...Link-->FC/CYA Levels
Click to expand...
Ok, thank you for the advice. FC was really high at 7 ppm the other day so I reduced the chorinator by 10% to see what it would do. Current output is 40%. I'll bump it back up and see if that gets us where we need to be.

Should I add a pound of stabilizer as well? And if so, should I do that before adding more acid or after?
 
Bjohn said:
Should I add a pound of stabilizer as well? And if so, should I do that before adding more acid or after?
Click to expand...
1lb of stabilizer will raise your CYA about 13. You should decide where you are going to run your CYA. Will my cell, I like to run CYA at 70. A good place to start when you are just learning your pool is 60 with SWCG. I would do it in 1lb increments. Let it dissolve, test 48 hours after it dissolves to retest.

You can and should manage pH separate from CYA. You can do both at the same time.
 
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Still battling high pH and from what I've read so far, this seems common for new pool startups. I'm curious what a "normal" amount of acid consumption is for new plaster pools around 10k gal.

I added another half gallon of acid on Saturday and got the best numbers I've seen yet, they're pasted below. By Monday pH was back up and I added more stabilizer to try to get CYA up to 50 at least.

It's worth noting, I have a Paramount ClearO3 ozonator. This was something I questioned our PB on early in the process but it seemed like continuing to push back on it would cause alienation during the build. It was already included in our contract price so it didn't seem worth it to nix it and drive a wedge between the PB. Now, I'm wondering if its responsible for a lot of the aeration I'm seeing and, in turn, driving the pH really high, really fast. Or is this normal pH creep for new builds?

==========================================
JB
------------------------------------------
Build Type: Plaster
Volume: 9000 gallons
------------------------------------------
Latest Test Result Summary:
FC: 8.0 (2 days ago)
CC: 0.5 (2 days ago)
pH: 7.5 (2 days ago)
TA: 60 (2 days ago)
CH: 400 (2 days ago)
CYA: 40 (2 days ago)
SALT: 4400 (2 days ago)
==========================================
 
I have a 9k pool that is 60 days old and I am using between 8-10 oz of MA per day with a TA of 70-90 (I just worked it down via aeration and it slowed the rise but still by 24 hrs later it’s at same place)

Like clockwork my ph is 8.1/8.2 in the morning and I dose it down to 7.6… repeat the next day.

I use the 20 Baumé strength
 
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Update: PB came out Friday and adjusted the ozonator. Turns out it was turned up pretty high. Aeration seems to be down after the adjustment and hopefully that helps keep the pH lower. Time will tell. Still adding about a quart of acid every other day to get it down to 7.6.

The scale I felt on and below the waterline tile seems much better. I'll still need to work right at the waterline to remove that scale but it shouldn't be too bad.
 
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