My pH rises by 0.4 every week

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lalittle

Well-known member
Apr 4, 2011
184
Los Angeles, CA
So what does it mean when you still see a significant pH rise in winter when the water is generally pretty cold (40's to 50's)? My pH still rises by 0.4 every week even though it's as cold as it ever gets in my area right now (Los Angeles area.) I let it rise to 7.8, then I knock it back down to 7.4, and I have to do this around once a week. The rise gets a bit faster in the summer when the water is warmer, but not "that" much faster. The plaster is a few years old now, so I don't see how that could be a factor, and I don't have any water features. I do have some aeration as evidenced by a light fog of tiny bubbles at some of the jets (I believe that the Kreepy Krauly is pulling in some air along the hose sections), which I posted about in another thread, but I'm still not clear if this could explain the rise.

Thanks,

Larry
 
JasonLion said:
The most likely possibility is that your TA is too high. Please post a complete set of water test results and we can give you a more specific answer.
Click to expand...

Water testing would definitely show any chemical issues that would cause pH rise, and is a great idea.

One other question OP, is this a Salt pool we are talking about?
 
It's not a salt pool -- I use a combination of liquid chlorine and pucks. I believe I have hit somewhat of a balance between liquid and pucks where my CYA level cycles through about the same range on a yearly basis. In other words, it rises over the summer, then drops over the winter as rain replaces water and I drain off the excess. I can't use all liquid because the level will plummet too quickly and get out of range too fast.

I don't think that the problem is TA being too high given that it's about 80 right now, and generally hovers between 70 and 80 over time.

The basic test rundown (Taylor K2006) right now is:

approx. 21K gallons
FC 6.0 (I generally try to stay between about 6 and 7.5 given my CYA levels.)
CC negligible (.5 or less)
pH 7.4
TA 80
CYA 70-ish

PS. Regarding the question of cold water effecting pH, is it ever recommended to maintain higher pH levels over the winter? I noticed that the Taylor Water Balance Calculator (the little cardboard disc) indicates that colder water at the same pH results in the water having a more acidic effect.
 
Water will naturally rise in pH as it gets colder and drop in pH as it gets warmer, ignoring any effects from carbon dioxide outgassing. So yes, you should normally let your pH be somewhat higher as the water gets colder and that will tend to keep the calcite saturation index from dropping too much. The only concern for higher pH is the increased risk of metal staining, if you have metal ions in your water.
 
lalittle said:
It's not a salt pool -- I use a combination of liquid chlorine and pucks. I believe I have hit somewhat of a balance between liquid and pucks where my CYA level cycles through about the same range on a yearly basis. In other words, it rises over the summer, then drops over the winter as rain replaces water and I drain off the excess. I can't use all liquid because the level will plummet too quickly and get out of range too fast.

I don't think that the problem is TA being too high given that it's about 80 right now, and generally hovers between 70 and 80 over time.

The basic test rundown (Taylor K2006) right now is:

approx. 21K gallons
FC 6.0 (I generally try to stay between about 6 and 7.5 given my CYA levels.)
CC negligible (.5 or less)
pH 7.4
TA 80
CYA 70-ish

PS. Regarding the question of cold water effecting pH, is it ever recommended to maintain higher pH levels over the winter? I noticed that the Taylor Water Balance Calculator (the little cardboard disc) indicates that colder water at the same pH results in the water having a more acidic effect.
Click to expand...

That makes sense. Sodium Hypochlorite has a pH of around 11. So adding it regularly will increase pH over time. Just be careful not to use too many TriChlor tablets at one time. I know its tempting to fill those 9lb chlorinators up, or put 2 or 3 tabs in each skimmer, but tabs have really low pH levels. I can safely tell you that Leslie's tabs (99%, 90% available) have a pH of 3. Plus, the CYA contained in the tabs can be too strong if too many tabs are present.

Another important thing is to make sure you steer clear of your return eyeballs when pulling a sample for testing. Especially if you have a chlorinator plumbed in by your equipment pad.

Hope this helps.
 
Big Bill said:
That makes sense. Sodium Hypochlorite has a pH of around 11. So adding it regularly will increase pH over time.
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This is not true. Sodium Hypochlorite is net PH neutral. When added it raises the PH, and then as the chlorine gets used up it lowers the PH back to almost exactly where it started.

lalittle, if you are losing CYA that quickly it is likely that you have a leak, unless you have way more rain than is typical in the US.

Your PH increase is most likely because of your TA level. Let TA fall to around 60 and see if PH will stabilize around 7.8. Holding the PH down below 7.8 will cause the PH to rise.
 
Big Bill said:
That makes sense. Sodium Hypochlorite has a pH of around 11. So adding it regularly will increase pH over time.
Click to expand...
Just for some real world experience, I use bleach exclusively and I might have to adjust my pH once or twice a season. It holds rock steady at about 7.5 pH all the time. If I run the fountain for an extended period of time I might have to adjust it a tiny bit. I have a gallon container of muriatic acid that's over three years old and it's not empty yet.
 
Thanks for the replies.

JasonLion said:
lalittle, if you are losing CYA that quickly it is likely that you have a leak, unless you have way more rain than is typical in the US.
Click to expand...

I had the system pressure tested for a leak by a "leak detection" service, but the tests showed no pressure loss, and the service guy was VERY confident that I did not have a leak. I also checked the water level drop by placing a bucket filled to a line with pool water on the top step of the pool (to maintain the same temp as the pool water) and comparing the level drop in the bucket to the drop in the pool. Even though I had what I considered a fairly rapid drop (a little over 1" in a week), the bucket lost the same amount, which seemed to indicate no leak. I did have a few instances where I had to drain some water (the tile along the top edge was fixed in a couple places), so that obviously brought the CYA down -- maybe I manually drained more over the year then I'm thinking. I do know that since I was aware of CYA buildup, I didn't hesitate to drain water, and in some cases drained a bit just to keep CYA down. I've been here less than two years, however, and I've only really been tracking the chemical levels for a single "full" year, so we'll see what happens over the next year.

Your PH increase is most likely because of your TA level. Let TA fall to around 60 and see if PH will stabilize around 7.8. Holding the PH down below 7.8 will cause the PH to rise.
Click to expand...

The TA was down around 60 at one point, but it rose a tad over time and stabilized at between 70 and 80. The lower TA didn't make the pH stabilize, but I never tried keeping it at 7.8 -- I always knocked it down at 7.4. I do know that if I let it go, it continues to rise above 7.8, so does this imply that it won't stabilize at 7.8? On that note, is it "okay" to let the pH stay that high? What effects will this have? I thought that you kind of "had" to keep the pH lower for eye comfort, to keep scaling down, and to help the Cl be more effective. If it rises above 7.8, how high should I let it go -- i.e. what range would I use? It seems to go against everything I've read to let it go to 8.0 or above.

To this day, I'm STILL unclear if the pH rise I'm seeing is "normal" or not. I see reports similar to Bama's above talking about only adding acid once or twice a season, which makes my acid consumption seem completely insane. Is there really THIS much of a variance to how much acid pools with no water features require?

Thanks again,

Larry
 
I checked my levels again and I believe my CYA is higher than I thought it was before -- it's closer to 80 or 90. So -- it hasn't dropped all the way down to where I started yet, and it's not likely to do so before the season starts again unless I drain a bunch more. I apparently drained more than I had thought last year, because it was lower at this time.

That's a side issue, howerver. The pH rise is what I'm trying to figure out here.

Larry
 

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lalittle said:
I checked my levels again and I believe my CYA is higher than I thought it was before -- it's closer to 80 or 90
Click to expand...
That makes a lot more sense.

The rate of PH increase depends on several factors. Lower PH means more PH increase and higher TA means more PH increase. By lowering TA and raising PH relative to where you have been you can slow the PH increase, though not necessarily stop it. However, if the TA tends to drift up to 70-80 on it's own, perhaps due to somewhat elevated TA levels in your fill water, it might be simpler to install an acid auto feed system.

Having the PH up around 7.8 is just fine, no significant effects, as long as your CH levels aren't unusually high and you don't have ongoing problems with metal stains. I didn't see you post a CH level. If CH is too high, say 600+, high PH can trigger calcium scaling.
 
JasonLion said:
I didn't see you post a CH level. If CH is too high, say 600+, high PH can trigger calcium scaling.
Click to expand...

My CH is around 475 by my best estimate. This is by far the most difficult test for me (even more so than CYA) given that the shift to blue (Taylore K2006) is very, VERY subtle, and I get a lot of pink blobbies that make it hard to see what's happening. I spoke with Taylor about this, but they said that it can sometimes be fairly difficult to get accurate results from this particular test. 475 is therefore a loose estimate, but this is still pretty far from the 600 that you mentioned, and my guess is that it's more likely that 475 is a high estimate.

Note that having said all that, I do have some calcium scaling, but it's only on the tiles that stick out of the water and form a flat surface separating the pool from the spa. These tiles get wet when the pump is on, but they dry off when the pump is off, and the scale forms in the grout lines where the water pools. I always figured that the scaling was due to the water sitting still and drying in between pump cycles.

Larry
 
257WbyMag said:
The calcium hardness test can be tough for some people. Here's an article by Taylor Technologies that may help you with that.

http://www.taylortechnologies.com/Chemi ... ntentID=70
Click to expand...

Thanks -- that's a helpful article.

Unfortunately, I spoke with Taylor a while back and had already tried the suggestions in the article. Adding some reagent ahead of time did not have any effect in my case -- I still get lots of pink globules that stay pink even after the water changes color. This has the effect of not only making it continue to look pink, but I believe it also "steals" saturation from the actual test, making the pink and then blue water color VERY subtle. My tests look nowhere NEAR as obvious as the examples they show. You can BARELY tell that the bulk of the water is pink, and then you can BARELY tell that it changed to blue. The effect is EXTREMELY subtle in my case, totally unlike the pictures they show. According to Taylor, you have to look at the water color and NOT the globule color, which seems nearly impossible in my case. They told me that if you continue to add reagent until the globules themselves change to blue, you'll get a falsely high reading.

Larry
 
lalittle said:
257WbyMag said:
The calcium hardness test can be tough for some people. Here's an article by Taylor Technologies that may help you with that.

http://www.taylortechnologies.com/Chemi ... ntentID=70
Click to expand...

Thanks -- that's a helpful article.

Unfortunately, I spoke with Taylor a while back and had already tried the suggestions in the article. Adding some reagent ahead of time did not have any effect in my case -- I still get lots of pink globules that stay pink even after the water changes color. This has the effect of not only making it continue to look pink, but I believe it also "steals" saturation from the actual test, making the pink and then blue water color VERY subtle. My tests look nowhere NEAR as obvious as the examples they show. You can BARELY tell that the bulk of the water is pink, and then you can BARELY tell that it changed to blue. The effect is EXTREMELY subtle in my case, totally unlike the pictures they show. According to Taylor, you have to look at the water color and NOT the globule color, which seems nearly impossible in my case. They told me that if you continue to add reagent until the globules themselves change to blue, you'll get a falsely high reading.

Larry
Click to expand...
I do a few things to deal with the same problems you're having.
1) Use a speedstir
2) Use the 10 ml sample
3) Add about half the R-0012 I think I'll need up front and run a full cycle on the speedstir.
4) Use 5 drops R-0011 instead of 3. It doesn't seem to affect the test results, because they're consistent either way, but it does make the color more intense and easier to watch.
 
Richard320 said:
lalittle said:
257WbyMag said:
The calcium hardness test can be tough for some people. Here's an article by Taylor Technologies that may help you with that.

http://www.taylortechnologies.com/Chemi ... ntentID=70
Click to expand...

Thanks -- that's a helpful article.

Unfortunately, I spoke with Taylor a while back and had already tried the suggestions in the article. Adding some reagent ahead of time did not have any effect in my case -- I still get lots of pink globules that stay pink even after the water changes color. This has the effect of not only making it continue to look pink, but I believe it also "steals" saturation from the actual test, making the pink and then blue water color VERY subtle. My tests look nowhere NEAR as obvious as the examples they show. You can BARELY tell that the bulk of the water is pink, and then you can BARELY tell that it changed to blue. The effect is EXTREMELY subtle in my case, totally unlike the pictures they show. According to Taylor, you have to look at the water color and NOT the globule color, which seems nearly impossible in my case. They told me that if you continue to add reagent until the globules themselves change to blue, you'll get a falsely high reading.

Larry
Click to expand...
I do a few things to deal with the same problems you're having.
1) Use a speedstir
2) Use the 10 ml sample
3) Add about half the R-0012 I think I'll need up front and run a full cycle on the speedstir.
4) Use 5 drops R-0011 instead of 3. It doesn't seem to affect the test results, because they're consistent either way, but it does make the color more intense and easier to watch.
Click to expand...


I have the same problem as lalittle re: the test. I'll try your method. Thanks.
 
Richard320 said:
I do a few things to deal with the same problems you're having.
1) Use a speedstir
2) Use the 10 ml sample
3) Add about half the R-0012 I think I'll need up front and run a full cycle on the speedstir.
4) Use 5 drops R-0011 instead of 3. It doesn't seem to affect the test results, because they're consistent either way, but it does make the color more intense and easier to watch.
Click to expand...

Other than using the speedstir, I tried these suggestions, but I still had the same problem. I still get a solution made up almost entirely of pink blobbies -- it only looks like a pink "solution" if I continue to swirl it. The color is VASTLY more subtle than the pictures on the Taylor site, and by the time I can see that the liquid "between" the blobbies is on the bluer side, the pink blobbies are also turning blue, which I was told indicates that too much reagent had been added. It's just a REALLY subtle color shift, even with the extra R-0011.

I don't know what is different about my water, but it just insists on coagulating into pink blobbies.

Thanks again,

Larry
 
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