Rancho Cost-a-Lotta

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Apr 10, 2018
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Your goal for CSI is somewhere between 0.0 and -0.30. This is the recommended CSI for plaster pools to mitigate scaling. Allowing your pH to rise to 7.8 ppm gets your CSI to -0.26. It looks like this is where your pool wants to be.

With borates, your pH rise will decrease. Unless I'm missing something, your chemistry looks good to me.
 

Bperry

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Aug 20, 2020
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Knoxville, TN
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TLDR: Have two concerning questions...
1) My CSI is -0.37 but modifying numbers in Pool Math, I don't see any way to get it close to 0 as even a pH of 8.0 only brings it to -0.20. If I increase CH to 450 and salt at 3600, it brings me to -0.27 with 7.6pH (-0.15 at 7.8pH). What do I do here?
2) TA is 70 even though I only ever increased this ONCE over three months ago when first balancing it, despite the insane amount of acid I put into this pool. How is that even possible?

It's BORATES DAY. Here's to hoping for the best because this is insane:

August 5th at 2pm pH was at 7.8. I added 6oz to bring it to 7.6. August 6th around 6pm it was 8.0!!! I added 12oz to bring it to 7.6 which I tested and confirmed at 9pm last night. Barely more than 12 hours later it was up to 7.8 so I added 8oz and tested to confirm it is now 7.6. This is simply RIDICULOUS.

Added 40lbs of Borates to bring the pool to 67. I read from some users who ran it slightly higher, and with my insane pH increase I'm really hoping to stabilize it a bit. I likely won't add anymore even next year unless the pH rise noticeably changes again, I figure I'll let it drift down on its own.

Test results before adding borates:
pH: 7.6
FC: 9.0
CC: 0.0
CYA: 70ish? I hate this test because I can ALWAYS see the dot in sunlight
CH: 340 -> 360 (added the last pound of the bag probably will go to about 360)
SALT: 3200 -> 3600 (added a 40lb bag to bring it to 3600)
TA: 70 (see question above)
CSI: -0.37 (pretty concerned about this)

i assume you’re looking down the tube for the CYA test and not through the side? Might be a dumb question but best to make sure. If you can see the dot looking down through the solution , then the test isn’t done. Your CYA may be lower than you think.
 

matthewsunshineflorida

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Sep 28, 2018
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Your goal for CSI is somewhere between 0.0 and -0.30. This is the recommended CSI for plaster pools to mitigate scaling. Allowing your pH to rise to 7.8 ppm gets your CSI to -0.26. It looks like this is where your pool wants to be.

With borates, your pH rise will decrease. Unless I'm missing something, your chemistry looks good to me.
If my CSI is in check, is it okay to allow the pH to stay around 7.8 to 8 instead of constantly bringing it down to 7.6? Just felt the water and it's noticeably silkier with the borates (is that a word?)... Interesting.


i assume you’re looking down the tube for the CYA test and not through the side? Might be a dumb question but best to make sure. If you can see the dot looking down through the solution , then the test isn’t done. Your CYA may be lower than you think.
Roger that! Yep I have had it tested at three different pool stores to get a gague for what a given level looks like, so I believe I'm relatively accurate but I just don't have trouble seeing the dot in the sunlight all the way up to nearly 0. In the shade it's much harder but I still normally would otherwise think it's lower than all the tests would say.

Also, I added a specific amount of CYA to bring it from 50 to 70 per the Pool Math app, so it does look to me around 70 what it previously looked like around 50 verified by the 3 pool stores. Still, just hate the test because it isn't immediately obvious like the others!
 

Rancho Cost-a-Lotta

Silver Supporter
Apr 10, 2018
2,494
Rancho Cucamonga, CA
Pool Size
18735
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Plaster
Chlorine
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SWG Type
CircuPool RJ-45
If my CSI is in check, is it okay to allow the pH to stay around 7.8 to 8 instead of constantly bringing it down to 7.6? Just felt the water and it's noticeably silkier with the borates (is that a word?)... Interesting.
TFP recommended range is 7.2 to 8.0 with 7.6 to 7.8 being "ideal." All is good.

Keep in mind, when the time comes to lower pH, more MA will be needed than before borates. For me, that amount is more than double.

I feel the same way about water feel and appearance. "Silkier" is a good descriptor (even if it's not a word). I added 50 ppm of borates to reduce scaling in my SWG. It worked for me.
 

Bperry

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Aug 20, 2020
1,071
Knoxville, TN
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If my CSI is in check, is it okay to allow the pH to stay around 7.8 to 8 instead of constantly bringing it down to 7.6? Just felt the water and it's noticeably silkier with the borates (is that a word?)... Interesting.



Roger that! Yep I have had it tested at three different pool stores to get a gague for what a given level looks like, so I believe I'm relatively accurate but I just don't have trouble seeing the dot in the sunlight all the way up to nearly 0. In the shade it's much harder but I still normally would otherwise think it's lower than all the tests would say.

Also, I added a specific amount of CYA to bring it from 50 to 70 per the Pool Math app, so it does look to me around 70 what it previously looked like around 50 verified by the 3 pool stores. Still, just hate the test because it isn't immediately obvious like the others!
You can bring the same test sample to 3 different stores and get a wildly different results. They aren’t any more accurate than your own test kit. Don’t use pool store tests to gauge the accuracy of your own test kit.
 

matthewsunshineflorida

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Sep 28, 2018
142
Tampa, FL
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You can bring the same test sample to 3 different stores and get a wildly different results. They aren’t any more accurate than your own test kit. Don’t use pool store tests to gauge the accuracy of your own test kit.

My thought is if there are 3 pool stores that all have the same CYA result and I'm not sure what to think about how the dot looks in my Taylor kit, it's probably a decent indication that the number they all give is roughly what the dot should look like at the given result. I'm not saying it's perfect, but it's better than my arbitrary guess based on nothing but a dot that never disappears...
 

Bperry

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Aug 20, 2020
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Knoxville, TN
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My thought is if there are 3 pool stores that all have the same CYA result and I'm not sure what to think about how the dot looks in my Taylor kit, it's probably a decent indication that the number they all give is roughly what the dot should look like at the given result. I'm not saying it's perfect, but it's better than my arbitrary guess based on nothing but a dot that never disappears...
I mean it’s very likely the stores will each have a different result. Check some of the threads here where people do that. One person was told the CYA was so high at 100ppm they’d need to drain the pool, but the testing with their own kit it was something like 50ppm. That’s a huge difference.

if the dot never disappears, then the CYA is lower than 30ppm.
 
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matthewsunshineflorida

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I mean it’s very likely the stores will each have a different result. Check some of the threads here where people do that. One person was told the CYA was so high at 100ppm they’d need to drain the pool, but the testing with their own kit it was something like 50ppm. That’s a huge difference.

if the dot never disappears, then the CYA is lower than 30ppm.
I must not be communicating clearly, my apologies, here's what I'm saying: My pool builder added enough CYA to get to 50ppm, tested, and told me that was the result. Then I take it to Pinch A Penny and they use a similar CYA test as me (subjective eyeball), and they get 50. Then I take it to Leslie's and they use their automated one and get like 52.1 or something nonsensically precise. Then I take it to a different Pinch A Penny and a different guy does an eyeball test and also gets 50.

Then I add a certain amount of CYA to bring it to 60 and take it in and everyone measures 60.

This continues to happen weekly for 3 months meaning different eyeballs, different tubes of chemicals, same result. Everyone is ending up with the same thing a solid dozen times.

So I'm not saying different pool stores are getting different results and I'm not sure who to trust. I'm saying they're getting roughly the same results as my Taylor kit for all values, and with CYA being the subjective test - they're still remarkably consistent across people, chemical batches, and machines.

So I have learned roughly what it's supposed to look like when I'm supposed to mark it, even though I can still see the dot well past it. Admittedly I definitely exaggerated about it NEVER disappearing all the way to 0 lol. I'm just saying I intentially go well past what I KNOW it is and still don't have a hard time making out the black dot when under direct sunlight.

I've definitely seen those nightmare threads you mention about pool stores being horribly wrong about CYA (and other measurements). I've done my best to read up on proper methodology checking CYA and people talking about what works for them. I get the "glance" thing, I've seen the discussions. I still don't feel CONFIDENT about this test simply because I can still see the dot past the result that is even possible for it to be.

Just messes with me a bit.
 
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matthewsunshineflorida

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Please clarify, how old is the plaster?
About 3.5 months. My main concern right now is the CSI at -0.37.

If I increase my CH to say 400, allow my pH to rise to 7.8-8 then I end up between -0.20 and -0.15. Is that a good plan?

I could also raise TA to 80 which then makes my CSI -0.08 to 0.02 at those numbers, but that's probably too high since every 10 degrees in temperature seems to raise it 0.09. Or I could raise CH to 450 and keep TA where it's at which takes me to -0.15 to -0.10.

Just concerned about how to get my CSI in check, I'm reading that a slight negative number is a good thing but it's pretty easy for that to swing a bit.
 
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ping

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Jun 24, 2011
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The pH rise is due to the new plaster and you don't want to go below -.2 for new plaster as JamesW stated towards the beginning of this thread. Let the pH run high, borates will limit the scaling inside the cell. Don't raise the CH, and just keep adding small amounts of acid to control the pH. It most likely wants to settle in at 8.0 and that is fine. Let it get that high for a few days and see how much acid it takes to drop it down to 7.6. Using poolmath you should be able to calculate how high the pH does get by how much acid it takes to drop it to 7.6. It will take more acid now that borates are in the water to get an equal amount of drop in pH.
 

matthewsunshineflorida

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Sep 28, 2018
142
Tampa, FL
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The pH rise is due to the new plaster and you don't want to go below -.2 for new plaster as JamesW stated towards the beginning of this thread. Let the pH run high, borates will limit the scaling inside the cell. Don't raise the CH, and just keep adding small amounts of acid to control the pH. It most likely wants to settle in at 8.0 and that is fine. Let it get that high for a few days and see how much acid it takes to drop it down to 7.6. Using poolmath you should be able to calculate how high the pH does get by how much acid it takes to drop it to 7.6. It will take more acid now that borates are in the water to get an equal amount of drop in pH.
Low CSI can increase pH rise from the plaster because the plaster releases calcium hydroxide.

High CSI can also be a problem as it can create scale.

Staying in the -0.2 to 0.0 range is probably ideal for newer plaster in my opinion.

Once the plaster is fully cured, -0.3 to 0.0 is fine.
That's all very helpful. But to be clear, I shouldn't add any CH even though it appears to increase the CSI bringing me more in check? At 7.8pH, at 80 degrees, and my salt now being 3600, I'm at -0.30 CSI but you're both saying I really should target above -0.20? I'm not sure how else to do that besides increasing CH, TA, or pH. What are your thoughts?
 

matthewsunshineflorida

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Sep 28, 2018
142
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Update: My pH is about 7.7 up just 0.1 after 55 hours which is by far the slowest rise I've ever seen. I'm really curious to see if it slows down and settles in the high 7s. I just bought 6 gallons of muriatic acid too - I was going through so much that I got used to pouring massive amounts of acid a couple times a week.

Anyway, that makes my CSI -0.33 with the following:
TA 70
CH 360
CYA 70
WT 80
Salt 3600
Borates 67

Even if it rises to 7.9 pH I'm only up to -0.24 CSI and you guys are saying to be above -0.20 so how on earth am I supposed to do that without raising CH, lowering CYA, or raising TA?
 

JamesW

TFP Expert
Mar 2, 2011
28,291
Even if it rises to 7.9 pH I'm only up to -0.24 CSI
Above -0.3 is fine.

Above -0.2 is better for new plaster, but I would not be too worried about -0.24, especially if the pH is staying stable.

I would even allow the pH to hit 8.0 as long as you can still read it accurately on the test.

If it hits 8.1, drop it to 8.0 or 7.9.
 
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matthewsunshineflorida

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Above -0.3 is fine.

Above -0.2 is better for new plaster, but I would not be too worried about -0.24, especially if the pH is staying stable.
Thanks James, so even though I'm at the very low end of "ideal" for SWG plaster CH - I should NOT raise CH to 400 or even 450 to help that CSI number? I'm confused as to why no one seems to suggest I do that - what am I not understanding?
 

JamesW

TFP Expert
Mar 2, 2011
28,291
In some places, calcium tends to build up and get too high.

As long as your calcium hardness does not tend to rise on its own due to high calcium fill water, then increasing the calcium a little bit is not a bad idea.

In places like AZ, the calcium will continuously rise to over 1,000 ppm due to evaporation and refill.

Once the CSI hits 0.0 or higher, the cell will tend to scale more.

However, you have borates, which help protect against scale.
 

matthewsunshineflorida

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Sep 28, 2018
142
Tampa, FL
Pool Size
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In some places, calcium tends to build up and get too high.

As long as your calcium hardness does not tend to rise on its own due to high calcium fill water, then increasing the calcium a little bit is not a bad idea.

In places like AZ, the calcium will continuously rise to over 1,000 ppm due to evaporation and refill.

Once the CSI hits 0.0 or higher, the cell will tend to scale more.

However, you have borates, which help protect against scale.
Gotcha, I wasn't sure if I was missing something about some kind of an unusual interaction with CH and Borates or CSI. I'm in Tampa Florida and I get a lot of chemical washout when it rains due to my overflow pipe being a foot and a half under the water so I've had to add a little CH and CYA just to maintain level. The only time I could imagine it not decreasing is during the winter months when we get very little rain. I'll test my fill water to make sure I could easily reduce if needed, then if no one has any red flags - I'll add a bag of 4lb CH to get it to 400 and leave it there for a while. Just that you guys have me paranoid about the CSI being perfect now!
 
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matthewsunshineflorida

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I have noticed my pH will settle at 8.0 with the following stats:
pH: 8.0
TA: 70
CH: 380
CYA: 50
SALT: 3500
BOR: 67
CSI: -.04

If I only take CYA back up to 60, my CSI is -0.10. I'm told this range is basically perfect, no?

Since it seems to just hang out at 8.0 and not go any higher, but my CSI is good - can I just leave it here?

To confirm I'm really at 8.0 and not higher, I do two drops of the acid demand reagent which gets me to matching 7.8, 4 drops matches 7.6, and 6 drops matches 7.4 - so I'm consistently at 0.2 per drop, meaning 8.0 should be spot on and isn't just me not being able to tell its much higher.
 

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