Dirk TFP has been a great find for you. You have been a great find for TFP! Thanks for sharing all you are doing and learning so others can learn with you. 
Kim
Kim
Water softener connected to auto fill, and new plaster start up.
- Thread starter Dirk
- Start date
- Nov 12, 2017
- 12,640
- Pool Size
- 12300
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- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Well, thanks. Being into/on/with/at TFP continues to be a fantastic experience for me (and my pool).
Update: Water is clear, leaves are gone, but the vacuum is exactly where it was yesterday. Which means it cleaned the whole pool then came right back to wait under the rain pipe!! It's a Pentair Rebel, but maybe has a little Kreepy Krauly in it!
- Nov 12, 2017
- 12,640
- Pool Size
- 12300
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Well... that was interesting. For kicks (and because I'm running out of excuses to avoid doing what I'm actually supposed to be doing today), I tested my rain water coming from the gutter. Not the pool after a rain, but rather my rain collection system fill water itself. Not at all what I expected! And not the deliciously pure water I was hoping for. The pH was the biggest surprise, as I was thinking it'd be off the scale acidic (as per the internet research of typical 5.5 rain water). The biggest disappointment was the TA and CH, both in the 40s!! And why there'd be any FC is a mystery, though not a concern. Test skew? Not sure. It was very pale pink, but definitely got clearer with one drop. Maybe this is all stuff what's running off the roof tiles somehow? It's not going to be the magic CH solution I was hoping for, for sure. I can still lower CH with the rain water, but it's not going to be as effective.
So I created a new Pool Math app "pool" to keep track. I'll try it again after a few heavier rains, to see if that cleans off the roof/gutters somewhat. And maybe I'll collect rain directly from the sky, to check the roof's contribution that way.
Good thing I didn't spend much on the rain collection setup! More later...
So I created a new Pool Math app "pool" to keep track. I'll try it again after a few heavier rains, to see if that cleans off the roof/gutters somewhat. And maybe I'll collect rain directly from the sky, to check the roof's contribution that way.
Good thing I didn't spend much on the rain collection setup! More later...
- May 23, 2015
- 25,699
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
You’re getting contamination from your roof and/or the container. I’m not surprised at all by the pH or TA but the CH a d FC are coming from an external contamination. CH I can easily see from dust/dirt/debris on the roof. FC is likely testing error.
- Nov 12, 2017
- 12,640
- Pool Size
- 12300
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Data!
These tests have their inherent margins of error, and I'm not as good at all these tests as I will be someday. I rinse everything in tap water first. And then in the test water just before the test. Even the mixer pill. I'm careful with measuring. I sometimes struggle with color, especially CH and Salt. But I've got enough here to see the trend I was after.
Rain water, collected in stainless steel bowl. Not sure how to test for "0" for TA, CH and Salt. Each changed color after one drop. These results are probably closer to 0 than the numbers I entered. pH bottomed out, color-wise, so I'm assuming it was some unknown amount less than 7.0:
Rain water, ollected from my concrete tile roof which now drains over my painted steel patio cover into an aluminum gutter and downspout and finally through a plastic corrugated drain pipe. As I mentioned, I was disappointed to find TA and CH. Salt was negligible:
If you haven't been following along, I recently modified my auto-fill system to be selectable between city water and my water softener, which is preceded by a whole-house water filter. Here's the city's fill water:
And the filtered soft water:
Here's today's pool water test results, right after the recent rains.
Conclusions!
Based on my previous test results, my own and those of the startup pool guy's and Leslie's, I am fairly certain I have been able to reduce and/or maintain CH and salt by using soft and rain water. I believe I saw some reduction just using the last two rains alone.
My filter and/or softener are doing a bang up job of reducing FC and CH. Not sure about salt. My pool's original fill salt test results were around 500. Which would indicate that was from the city fill water. Now the pool's salt seems to be a bit lower, and the city water is testing little or no salt. Lots of room for error with this data. I think it is safe to assume city water can vary over time. I'll track it a few times a year and see if there's a trend.
I was disappointed to learn that my softener and filter are passing TA, apparently straight through. I don't really understand TA, at all, so I don't know what to think about that. I've been assured that TA will stabilize itself. And considering my increased use of MA for the SWG, I'm hopeful that will be true and that my fill water TA won't push up the pool's TA.
I had originally seen more CH in my soft water fill water than I am seeing today (I once tested it at 60). That could have been city water in the line, not sure. Today it's at 0 and that is spectacular!!
So... I think my soft water fill system is a success. If certainly will slow CH build up, and could conceivably eliminate it, if not reverse it. Time will tell. I'm concluding modifying the fill system was worth the effort.
The rain water fill system is a bust. Good thing it only cost me $10! But it's solved a drainage issue, so it was beneficial otherwise. There are just too many downsides: I have to manage the draining prior to a rain. That draining will mess with my CYA level. The "gutter water" doesn't have the CH reducing goodness of my soft water. And this experiment has made me realize that it is putting "stuff" in my water. Not just CH and TA, but who knows what. I hadn't really thought that through. I thought after x-years the roof and gutters would be clean-ish, but maybe a tad dusty (something my filter could handle). But I've come to realize there could be anything falling to the roof, and certainly bird fecal matter is one of those things. Now that junk lands in the pool all on its own, but I'm just increasing the volume of it by using roof/gutter water. So while the roof water is free, and would save on water costs and softener wear and tear in the winter, it's just not beneficial enough to outweigh the contaminants it'd add to the water.
So "Yay" on the soft water fill system. "Nay" on the rain water fill system.
Now if anyone has been bored enough to follow along with this adventure (for which I thank you), I'm guessing you might be nodding your head(s) right now, along the lines of "Could'a told him that. But this guy's gotta figure all this stuff out for himself!" That's cool. I do, indeed, sometimes need to see things for myself. But now I've got my results, and I think, ultimately, my pool will be better off for it. :blah:
Now I just have to go buy some more reagents!!
These tests have their inherent margins of error, and I'm not as good at all these tests as I will be someday. I rinse everything in tap water first. And then in the test water just before the test. Even the mixer pill. I'm careful with measuring. I sometimes struggle with color, especially CH and Salt. But I've got enough here to see the trend I was after.
Rain water, collected in stainless steel bowl. Not sure how to test for "0" for TA, CH and Salt. Each changed color after one drop. These results are probably closer to 0 than the numbers I entered. pH bottomed out, color-wise, so I'm assuming it was some unknown amount less than 7.0:
Rain water, ollected from my concrete tile roof which now drains over my painted steel patio cover into an aluminum gutter and downspout and finally through a plastic corrugated drain pipe. As I mentioned, I was disappointed to find TA and CH. Salt was negligible:
If you haven't been following along, I recently modified my auto-fill system to be selectable between city water and my water softener, which is preceded by a whole-house water filter. Here's the city's fill water:
And the filtered soft water:
Here's today's pool water test results, right after the recent rains.
Conclusions!
Based on my previous test results, my own and those of the startup pool guy's and Leslie's, I am fairly certain I have been able to reduce and/or maintain CH and salt by using soft and rain water. I believe I saw some reduction just using the last two rains alone.
My filter and/or softener are doing a bang up job of reducing FC and CH. Not sure about salt. My pool's original fill salt test results were around 500. Which would indicate that was from the city fill water. Now the pool's salt seems to be a bit lower, and the city water is testing little or no salt. Lots of room for error with this data. I think it is safe to assume city water can vary over time. I'll track it a few times a year and see if there's a trend.
I was disappointed to learn that my softener and filter are passing TA, apparently straight through. I don't really understand TA, at all, so I don't know what to think about that. I've been assured that TA will stabilize itself. And considering my increased use of MA for the SWG, I'm hopeful that will be true and that my fill water TA won't push up the pool's TA.
I had originally seen more CH in my soft water fill water than I am seeing today (I once tested it at 60). That could have been city water in the line, not sure. Today it's at 0 and that is spectacular!!
So... I think my soft water fill system is a success. If certainly will slow CH build up, and could conceivably eliminate it, if not reverse it. Time will tell. I'm concluding modifying the fill system was worth the effort.
The rain water fill system is a bust. Good thing it only cost me $10! But it's solved a drainage issue, so it was beneficial otherwise. There are just too many downsides: I have to manage the draining prior to a rain. That draining will mess with my CYA level. The "gutter water" doesn't have the CH reducing goodness of my soft water. And this experiment has made me realize that it is putting "stuff" in my water. Not just CH and TA, but who knows what. I hadn't really thought that through. I thought after x-years the roof and gutters would be clean-ish, but maybe a tad dusty (something my filter could handle). But I've come to realize there could be anything falling to the roof, and certainly bird fecal matter is one of those things. Now that junk lands in the pool all on its own, but I'm just increasing the volume of it by using roof/gutter water. So while the roof water is free, and would save on water costs and softener wear and tear in the winter, it's just not beneficial enough to outweigh the contaminants it'd add to the water.
So "Yay" on the soft water fill system. "Nay" on the rain water fill system.
Now if anyone has been bored enough to follow along with this adventure (for which I thank you), I'm guessing you might be nodding your head(s) right now, along the lines of "Could'a told him that. But this guy's gotta figure all this stuff out for himself!" That's cool. I do, indeed, sometimes need to see things for myself. But now I've got my results, and I think, ultimately, my pool will be better off for it. :blah:
Now I just have to go buy some more reagents!!
- May 23, 2015
- 25,699
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Softeners don't remove alkalinity (primarily from carbonates). Water softeners should really be referred to as cation exchange filters because the exchange resin only works on positively charged cations (Na+ and Ca2+ ions). The exchange resin completely ignores the negative ions (CO3[2-] and HCO3[-]). There are such things as anionic exchange resins that can remove negative ions like carbonates and nitrates but those filters are SUPER expensive, not for residential use and require very precise input water conditions or else they'll get ruined.
Nice experiment. Where I am, roof water is perfectly acceptable to use and one of these days I'll get around to redirecting a gutter. Dust and bird droppings don't really matter as that is why you have a filter and chlorine in your pool.
Nice experiment. Where I am, roof water is perfectly acceptable to use and one of these days I'll get around to redirecting a gutter. Dust and bird droppings don't really matter as that is why you have a filter and chlorine in your pool.
- Nov 12, 2017
- 12,640
- Pool Size
- 12300
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
OK, so TA is what it is. I'll fight that battle if and when I need to. I was able to successfully "TFP" reduce it, so I know how, and it's been stable anyway. So non-issue for now. Thanks for the explanation.
Does it ring true that my CH would be 0 out of the softener, and the previous result of 60 was more likely a test error?
I was counting on the roof water being acceptable, and maybe it is. But my filtered soft water is the better solution for CH, and the cost differential between soft and rain does not outweigh the work of managing the rain water (neither the savings or the work are much at all, just kind'a a wash).
All academic, since it's never going to rain in California again...
Does it ring true that my CH would be 0 out of the softener, and the previous result of 60 was more likely a test error?
I was counting on the roof water being acceptable, and maybe it is. But my filtered soft water is the better solution for CH, and the cost differential between soft and rain does not outweigh the work of managing the rain water (neither the savings or the work are much at all, just kind'a a wash).
All academic, since it's never going to rain in California again...
- May 23, 2015
- 25,699
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
The water out of the softener will have varying levels of calcium that change with age and use of the resin...all of it will be well below what your test kit is capable of measuring. So it’s not really “0” in reality but, for practical purposes, you can consider it to be < 10ppm. That’s good enough for pool fill water.
- Nov 12, 2017
- 12,640
- Pool Size
- 12300
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Awesome, thanks!
Measure twice, cut once!! I had pursued the rain water fill system because I was trying to do better than the CH60 I thought my softener was producing. I just assumed that's what it was going to be. I knew I was going to do another whole test suite, but it didn't occur to me to do so before I did my rain dance. Lesson learned...
- Nov 12, 2017
- 12,640
- Pool Size
- 12300
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Matt,
Would you expect either a whole house filter (Lowes) and/or water softener (also Lowes) to reduce salt?
Would you know... Does my city's TA230 surprise you? Is that low/normal/high for a municipal water supply? They draw my water from wells, fed by the Salinas river. It is supplemented in varying amounts throughout the year with lake water (which affects the hardness). No matter, I've seen that 200+ result a few times now, so I don't think its test error. We're surrounded by agriculture.
Would you expect either a whole house filter (Lowes) and/or water softener (also Lowes) to reduce salt?
Would you know... Does my city's TA230 surprise you? Is that low/normal/high for a municipal water supply? They draw my water from wells, fed by the Salinas river. It is supplemented in varying amounts throughout the year with lake water (which affects the hardness). No matter, I've seen that 200+ result a few times now, so I don't think its test error. We're surrounded by agriculture.
Dirk that was a very neat and well done try and write up! Thanks for doing it and sharing it!
Kim
Kim
- Nov 12, 2017
- 12,640
- Pool Size
- 12300
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Re: Water softener connected to auto fill, and new plaster start up.
I've been using this advice with great success. But...
I just had a conversation with Wayne from Taylor. I was asking him about the accuracy of their K2006 tests. In the course of our conversation, I asked him about this 4-drop idea. He was quite adamant that this was not a good idea, and insisted the accuracy of the pH test depends on 5 drops.
Personally, I like the 4 drop idea, but thought I should pass Wayne's thoughts along (he is Taylor's tech support guy, and has been with them for quite some time).
By the way, this is what he told me regarding accuracy. If all tests are performed perfectly (and he said this is true across the industry):
The accuracy of their drop tests is within 10%.
The accuracy of their color matching tests is ± half the difference between two standards. Huh? I had to have him clarify that. For example: my pH test vial's standards are 0.2 apart (7.2, 7.4, 7.6, etc). Half that difference is 0.1. So if I do my pH test and get 7.6, my actual pH is between 7.5 and 7.7.
We also talked about interpolation (which I've been doing). So using pH again as an example: if my test water is not quite "yellow enough" to be 7.6, or "pink enough" to be 7.8, then it's fair to claim 7.7. But with the accuracy factor, the actually pH could be between 7.6 and 7.8.
He admitted that the CYA test is another whole animal, and is so subjective that it is only reliable enough to get you in the ballpark (I'm paraphrasing). He couldn't, or wouldn't, associate any sort of accuracy number to the CYA test.
In the grand scheme of things, this accuracy is more than adequate for pool maintenance, but thought it was interesting enough to share nonetheless.
The call to Taylor was inspired by the CYA test result. It's unfortunate that a number that is so critical to proper FC (and pool) maintenance is so difficult to accurately obtain.
I've been using this advice with great success. But...
I just had a conversation with Wayne from Taylor. I was asking him about the accuracy of their K2006 tests. In the course of our conversation, I asked him about this 4-drop idea. He was quite adamant that this was not a good idea, and insisted the accuracy of the pH test depends on 5 drops.
Personally, I like the 4 drop idea, but thought I should pass Wayne's thoughts along (he is Taylor's tech support guy, and has been with them for quite some time).
By the way, this is what he told me regarding accuracy. If all tests are performed perfectly (and he said this is true across the industry):
The accuracy of their drop tests is within 10%.
The accuracy of their color matching tests is ± half the difference between two standards. Huh? I had to have him clarify that. For example: my pH test vial's standards are 0.2 apart (7.2, 7.4, 7.6, etc). Half that difference is 0.1. So if I do my pH test and get 7.6, my actual pH is between 7.5 and 7.7.
We also talked about interpolation (which I've been doing). So using pH again as an example: if my test water is not quite "yellow enough" to be 7.6, or "pink enough" to be 7.8, then it's fair to claim 7.7. But with the accuracy factor, the actually pH could be between 7.6 and 7.8.
He admitted that the CYA test is another whole animal, and is so subjective that it is only reliable enough to get you in the ballpark (I'm paraphrasing). He couldn't, or wouldn't, associate any sort of accuracy number to the CYA test.
In the grand scheme of things, this accuracy is more than adequate for pool maintenance, but thought it was interesting enough to share nonetheless.
The call to Taylor was inspired by the CYA test result. It's unfortunate that a number that is so critical to proper FC (and pool) maintenance is so difficult to accurately obtain.
- May 23, 2015
- 25,699
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Re: Water softener connected to auto fill, and new plaster start up.
Taylor's warnings are appropriate because color interpretation is a very tricky thing. There are two things to understand about pH indicators -
1. The color, or hue, of the solution is set by the pH of solution and the pKa of indicator dye.
2. The saturation of the color (also known has the chroma or intensity) is determined by the concentration of that color in the solution
To point #1, the chemistry is simple acid/conjugate base reaction -
HIn = protonated Indicator molecule (yellow color)
H+ = acid proton in solution
In- = Negatively charge form of the indicator dye with proton removed (red color)
HIn(aq) <-----> H+ (aq) + In- (aq)
Ka = ([H+]*[In-]) / [HIn]
or, if we do some fancy math with logarithms, you eventually get the Henderson-Hasselbalch equation -
pH = pKa + log([In-]/[HIn])
So, the ratio of the deprotonated form of the phenol red indicator ([In-] which optically looks red colored) and the protonated form of the phenol red indicator ([HIn] which optically looks yellow) is strictly determined by the difference between the pH of the solution and the pKa of the chemical compound. So, the hue (which would be a mixture of red and yellow) is set entirely by the pH of the solution since the pKa is a constant. So the ratio never changes but, as the total concentration of those chemicals is reduced in solution, whatever the hue is, it's saturation will decrease towards white (colorless on a white background).
There is also the added complexity that you are comparing your solution color to a color standard sitting next to it. That color standard has a hue and saturation that is defined by the concentration of the dye in the medium. So, when Taylor makes their comparator block, they are trying to exactly match the hue and saturation of the indicators color at a given pH.
I did a test of 5 drops versus 4 drops side by side since I have two #9056 comparator tubes -
5 drops of R-0004
4 drops of R-0004
PS - The answer is 7.6 ....
I'm sure the forum software will downgrade the image resolution but, if you could see them on my phone, you might be tempted to think they are different colors. They are not. In the bright sun with my white background they are clearly the same color just a slightly different saturation or intensity due to the 20% lower concentration in solution. As I see them, the 5 drop sample looks closest to the 7.6 color patch on the tube.
I also have R-0014 drops and the midget comparator tube that's similar to what is found in the K-1000 or K-1001 kits. That comparator has a 7.5 pH color swatch on it and the color of the solution does not look like 7.5 but between 7.5 and 7.8 on that midget tube.
Taylor's warnings are appropriate because color interpretation is a very tricky thing. There are two things to understand about pH indicators -
1. The color, or hue, of the solution is set by the pH of solution and the pKa of indicator dye.
2. The saturation of the color (also known has the chroma or intensity) is determined by the concentration of that color in the solution
To point #1, the chemistry is simple acid/conjugate base reaction -
HIn = protonated Indicator molecule (yellow color)
H+ = acid proton in solution
In- = Negatively charge form of the indicator dye with proton removed (red color)
HIn(aq) <-----> H+ (aq) + In- (aq)
Ka = ([H+]*[In-]) / [HIn]
or, if we do some fancy math with logarithms, you eventually get the Henderson-Hasselbalch equation -
pH = pKa + log([In-]/[HIn])
So, the ratio of the deprotonated form of the phenol red indicator ([In-] which optically looks red colored) and the protonated form of the phenol red indicator ([HIn] which optically looks yellow) is strictly determined by the difference between the pH of the solution and the pKa of the chemical compound. So, the hue (which would be a mixture of red and yellow) is set entirely by the pH of the solution since the pKa is a constant. So the ratio never changes but, as the total concentration of those chemicals is reduced in solution, whatever the hue is, it's saturation will decrease towards white (colorless on a white background).
There is also the added complexity that you are comparing your solution color to a color standard sitting next to it. That color standard has a hue and saturation that is defined by the concentration of the dye in the medium. So, when Taylor makes their comparator block, they are trying to exactly match the hue and saturation of the indicators color at a given pH.
I did a test of 5 drops versus 4 drops side by side since I have two #9056 comparator tubes -
5 drops of R-0004
4 drops of R-0004
PS - The answer is 7.6 ....
I'm sure the forum software will downgrade the image resolution but, if you could see them on my phone, you might be tempted to think they are different colors. They are not. In the bright sun with my white background they are clearly the same color just a slightly different saturation or intensity due to the 20% lower concentration in solution. As I see them, the 5 drop sample looks closest to the 7.6 color patch on the tube.
I also have R-0014 drops and the midget comparator tube that's similar to what is found in the K-1000 or K-1001 kits. That comparator has a 7.5 pH color swatch on it and the color of the solution does not look like 7.5 but between 7.5 and 7.8 on that midget tube.
- Nov 12, 2017
- 12,640
- Pool Size
- 12300
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Sorry Matt, I read your explanation (well, OK, most of it) and at first pass I'm hearing that you're contradicting Taylor, though you begin stating their "warnings are appropriate." Not that I don't trust Marty, but I had originally run some comparisons too, before I adopted the 4-drop method, and couldn't discern an appreciable difference (though I only had one tester). Are you saying that 4 drops and 5 drops produce the exact same hue, or should I follow Taylor's warning and only use 5 drops, because 4 drops result in a different chemical reaction and therefore a different hue?
And, sidebar, I've also wondered how my comparison method affects results. In my profession I often have to compare color on a computer monitor to color on a printed piece of paper. The mediums are so different, reflective vs emitted light, and the color models are so different (RGB vs CMYK) that it's near impossible. It's become more of an art than a science to do it right. I digress. But that's my foundation for questioning the effectiveness of comparing the color of water to the color of color-impregnated plastic (or whatever it is). Further compounded by my lighting. I've taken to reflecting some "relatively white" LED light off a "relatively white" card through the tester to my eyes. This makes it the easiest for me to compare, and makes the testing procedure very consistent (as opposed to testing outside under various cloud conditions and times of day), but I have no idea if the light I'm shining through the tester is altering the results in some way. Or if that even matters, as it might all be relative. Thoughts?
And while I've got your brain on this path: I used to use two scoops of "FC powder" but then figured because I typically only test a 10ml sample, that I could half that to one scoop (slightly rounded). I tested this too, and couldn't see any appreciable difference between one or two scoops. The Taylor instructions don't indicate using half as much for a 10ml sample, but rather spec 2 scoops for either the 10ml or 25ml test. I'm not sure if this was an oversight by the instruction's author, or if Taylor really wants us to use 2 scoops regardless of sample size. But one scoop seems to work. Thoughts?
And, sidebar, I've also wondered how my comparison method affects results. In my profession I often have to compare color on a computer monitor to color on a printed piece of paper. The mediums are so different, reflective vs emitted light, and the color models are so different (RGB vs CMYK) that it's near impossible. It's become more of an art than a science to do it right. I digress. But that's my foundation for questioning the effectiveness of comparing the color of water to the color of color-impregnated plastic (or whatever it is). Further compounded by my lighting. I've taken to reflecting some "relatively white" LED light off a "relatively white" card through the tester to my eyes. This makes it the easiest for me to compare, and makes the testing procedure very consistent (as opposed to testing outside under various cloud conditions and times of day), but I have no idea if the light I'm shining through the tester is altering the results in some way. Or if that even matters, as it might all be relative. Thoughts?
And while I've got your brain on this path: I used to use two scoops of "FC powder" but then figured because I typically only test a 10ml sample, that I could half that to one scoop (slightly rounded). I tested this too, and couldn't see any appreciable difference between one or two scoops. The Taylor instructions don't indicate using half as much for a 10ml sample, but rather spec 2 scoops for either the 10ml or 25ml test. I'm not sure if this was an oversight by the instruction's author, or if Taylor really wants us to use 2 scoops regardless of sample size. But one scoop seems to work. Thoughts?
- May 23, 2015
- 25,699
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
The Taylor phenol red indicator (either R-0004 or R-0014) is actually a mixture of phenol red and dechlorinating chemicals (the dechlorinating is achieve by two chemicals designed to produce a pH neutral reaction). Phenol red is sensitive to chlorine and it’s presence can cause the phenol red to become chlorophenol red which is a pH indicator at a much lower range (4.8-6.7). It becomes purple/magenta above a pH of 6.7 and so it can cause a false color to develop.
So, while I don’t dispute Wayne’s admonition that the test should be followed as-written, his explanation is somewhat off track. There is no “other chemical reactions” that will happen or not happen because of one less drop. Phenol red changes color based on pH alone, full stop. The hue and saturation of that color is set by pH and concentration, that’s it. The only other reactions that occurs are the dechlorinating reactions and those are designed to handle FC levels up to 10ppm. So unless your FC is very high, there should be no color changes other than those caused by pH.
If Taylor engineered their comparator cell properly, then the hue and saturation of the color blocks embedded in the plastic should be equal to the hue and saturation of the colored water in the tube. As an engineer I can describe how one would analytically go about doing that but, suffice it to say, I think Taylor is enough of a straight up company to do what is right. As the consumer, you have to simply assume (and trust) that they are doing their job right. I personally think they’re a good company so I trust them to do the right kind of basic product engineering work.
I personally don’t really use the 10mL test method and I always do 25mL x 2 scoops. The powder is a complex mixture of indicator dye and pH buffers as well as metal ion sequestrants. Using less than 2 full scoops can sometime be a problem if the FC is very high as you can get a false low reading. Honestly, it’s penny-wise/pound-foolish to cut back on powder scoops. The reagent is comparatively cheap in the grand scheme of pool care costs. The cost savings is irrelevant and trying to stretch out power use over multiple seasons can just lead to compromised reagents. It’s really not worth it in my opinion.
So, while I don’t dispute Wayne’s admonition that the test should be followed as-written, his explanation is somewhat off track. There is no “other chemical reactions” that will happen or not happen because of one less drop. Phenol red changes color based on pH alone, full stop. The hue and saturation of that color is set by pH and concentration, that’s it. The only other reactions that occurs are the dechlorinating reactions and those are designed to handle FC levels up to 10ppm. So unless your FC is very high, there should be no color changes other than those caused by pH.
If Taylor engineered their comparator cell properly, then the hue and saturation of the color blocks embedded in the plastic should be equal to the hue and saturation of the colored water in the tube. As an engineer I can describe how one would analytically go about doing that but, suffice it to say, I think Taylor is enough of a straight up company to do what is right. As the consumer, you have to simply assume (and trust) that they are doing their job right. I personally think they’re a good company so I trust them to do the right kind of basic product engineering work.
I personally don’t really use the 10mL test method and I always do 25mL x 2 scoops. The powder is a complex mixture of indicator dye and pH buffers as well as metal ion sequestrants. Using less than 2 full scoops can sometime be a problem if the FC is very high as you can get a false low reading. Honestly, it’s penny-wise/pound-foolish to cut back on powder scoops. The reagent is comparatively cheap in the grand scheme of pool care costs. The cost savings is irrelevant and trying to stretch out power use over multiple seasons can just lead to compromised reagents. It’s really not worth it in my opinion.
Dirk I am going to stink my nose in and chime in. When Matt shows the two examples of his PH test he says BOTH the 4 drops and 5 drops test show the PH as the same level 7.6. That leads me to believe both 4 and 5 drops give the same results in the end. Do what works for you and your pool. Does you pool sparkle and shine? Is it algae free? If both are yes then your way is working for you!
Kim
Kim
- Oct 25, 2015
- 5,813
- Pool Size
- 28000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60 Plus
Re: Water softener connected to auto fill, and new plaster start up.
Matt suggested this to me a while back because I have a form of color-blindness common in men that makes the red shades very difficult to discern. I actually switched to pocked PH meters (and calibration fluids) for a while. With the 4 drop test I was able to "train" myself to use the drop test. To do the test successfully I must have good light and a white background. Now it's very repeatable even for me.
Chris
Matt suggested this to me a while back because I have a form of color-blindness common in men that makes the red shades very difficult to discern. I actually switched to pocked PH meters (and calibration fluids) for a while. With the 4 drop test I was able to "train" myself to use the drop test. To do the test successfully I must have good light and a white background. Now it's very repeatable even for me.
Chris
- May 23, 2015
- 25,699
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
It’s really about finding the thing that works for you and sticking with it. Some folks prefer digital meters and that’s ok. Some people prefer drops in other kits, and that’s ok too. I find 5 drops of R-0004 in the big tube works fine for me. I have a really hard time using the R-0014 drops in the midget comparator even though the chemistry is the same. So it’s just about finding out what works.
Also, as far as analytical chemistry goes, pH indicators have never been an exact method for measuring pH. In chemistry labs they are most often used in conjunction with pH probes to give the lab worker a visual endpoint detection so they know when to stop a specific test. pH indicators are almost always used to give a broad reading of pH, not a specific value.
This is why Taylor indicates that the resolution is +/- 0.1 units as that is about the best color discrimination one can get.
Also, as far as analytical chemistry goes, pH indicators have never been an exact method for measuring pH. In chemistry labs they are most often used in conjunction with pH probes to give the lab worker a visual endpoint detection so they know when to stop a specific test. pH indicators are almost always used to give a broad reading of pH, not a specific value.
This is why Taylor indicates that the resolution is +/- 0.1 units as that is about the best color discrimination one can get.
- Nov 12, 2017
- 12,640
- Pool Size
- 12300
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Well, my concerns about accuracy and methods are two fold. I started sharing the 4-drop trick with others here (including another guy with the same "seeing reds" issue) and I wanted to make sure I wasn't blowing smoke. I just did a 5-drop test and it was fine, but a bit harder for me to match than the 4-drop tests I've been doing.
And I get that this isn't lab-quality stuff we're doing here, but the other issue is my plaster.
I'm bound and determined to do what I can to make this new pebble my last surface repair/replacement. I'm shooting for 30 years!! I don't want to save for another one. I don't ever want to need to acid wash again (I learned my lesson). And I don't want to look at calcium deposits. So... with 50ish water temps, new plaster/pebble, and a somewhat exaggerated need to maintain perfect balance, I've been riding my pH at the upper end of the scale. And since I've been seeing multiple ideas about what that upper end actually is, I'm looking to minimize testing errors and margins as much as reasonably possible. Did I lose ya?
I know TFP teaches 7.2 to 7.8. But my NPC startup card and other sources often site 7.6 as the max. TFP also sites a slightly negative CSI as ideal. So in my pool's world, at it's current temp, TA, and salt level, my CSI is happiest when my pH is right around 7.7 (right in between the prevailing difference of opinion about the max). Plus, it's still drifting up from being new, so even if I compensate and adjust it to 7.6, it can still creep up to 7.8 on me. Which, according to Taylor, could actually be 7.9! I'm probably overthinking this a bit, but I'm still wondering: which is better for my plaster's long term health? Keeping the pH well below the upper range? Or keeping the CSI just below zero? With temps in the 50s and salt around 500, I can't do both. Later (according to Pool Math) when I add the salt for my SWG, and the water temp rises, I'll be able to maintain optimum CSI (just negative of 0) and optimum pH (around 7.5). But then next winter, with all the salt, and temps down to the 40s I'll have an even bigger challenge to maintain best pH and CSI.
I figure I can only do what I can do, but that won't keep me from attempting to do the best I can do...
If you all had to choose... which: the better pH, or the better CSI?
And I get that this isn't lab-quality stuff we're doing here, but the other issue is my plaster.
I'm bound and determined to do what I can to make this new pebble my last surface repair/replacement. I'm shooting for 30 years!! I don't want to save for another one. I don't ever want to need to acid wash again (I learned my lesson). And I don't want to look at calcium deposits. So... with 50ish water temps, new plaster/pebble, and a somewhat exaggerated need to maintain perfect balance, I've been riding my pH at the upper end of the scale. And since I've been seeing multiple ideas about what that upper end actually is, I'm looking to minimize testing errors and margins as much as reasonably possible. Did I lose ya?
I know TFP teaches 7.2 to 7.8. But my NPC startup card and other sources often site 7.6 as the max. TFP also sites a slightly negative CSI as ideal. So in my pool's world, at it's current temp, TA, and salt level, my CSI is happiest when my pH is right around 7.7 (right in between the prevailing difference of opinion about the max). Plus, it's still drifting up from being new, so even if I compensate and adjust it to 7.6, it can still creep up to 7.8 on me. Which, according to Taylor, could actually be 7.9! I'm probably overthinking this a bit, but I'm still wondering: which is better for my plaster's long term health? Keeping the pH well below the upper range? Or keeping the CSI just below zero? With temps in the 50s and salt around 500, I can't do both. Later (according to Pool Math) when I add the salt for my SWG, and the water temp rises, I'll be able to maintain optimum CSI (just negative of 0) and optimum pH (around 7.5). But then next winter, with all the salt, and temps down to the 40s I'll have an even bigger challenge to maintain best pH and CSI.
I figure I can only do what I can do, but that won't keep me from attempting to do the best I can do...
If you all had to choose... which: the better pH, or the better CSI?
- May 23, 2015
- 25,699
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
My opinion - you are waaaaaaaaay over-thinking this AND you are placing way too much trust in the NPC and plaster manufacturers recommendation. Try reading some threads written here by one of TFP's plaster experts, onBalance. Very little of what plasterers and the NPC technical committee does is based on rational science.
As for which is better, pH or CSI, that's a false choice. pH is a component of CSI and, if you keep your CSI balanced, then it doesn't matter what your pH is...the water is balanced, period, full-stop. CSI is a mathematical expression of the saturation of calcium carbonate in pool water relative to what it's theoretical value is based on current pH, TA, etc. So, when your CSI is negative, that means that there slightly less calcium in the water than what the water can actually hold. So the driving force is for calcium to remain in the water and for sources of calcium, ie, your plaster, to want to liberate calcium into the water. A positive CSI means that your water is has slightly more calcium in it than what it can theoretically hold and so the calcium that is in the water wants to precipitate out of solution (typically in the form of calcium carbonate scale). A CSI of zero means that there is exactly the amount of calcium in solution that the water can theoretically hold.
However, CSI is an "unstable equilibrium", that is, it's like trying to balance a bowling ball on the tip of pointed stick. As long as you are actively managing the position of the stick, you can reasonably keep the bowling ball balanced. But, there is always a driving force for the bowling ball to want to fall one way or the other. The same is true for CSI - there is no way to perfectly maintain a CSI of 0 without actively correcting pH, TA, etc. It will always tend to go positive (most of the time) or negative (only under certain circumstances).
With that said, CSI only tells you that there is a driving force that exists to push or pull calcium into or out of solution. It tells you nothing about how fast that will happen. Even if the CSI is negative, the reaction rate and etching rates can be so slow that you will never notice or see the effect. The same is true for scaling - the rate can be entirely imperceptible. This is why TFP says that a CSI within in the range of -0.3 to +0.3 is fine - in that range, there is really no significant scaling or etching that will occur. In fact, the data suggests that you would need of very negative CSI, less than -0.7, for many months before any noticeable etching of the plaster would take place. The same is true for scaling - it is typically only seen inside harsh environment such as your pool heater heat exchanger or inside the SWG cell where the CSI can become very positive either due to high heat or high pH.
You will likely find it very difficult to keep your water anywhere near a pH of 7.5 for any length of time without consistent, daily acid additions. Water with carbonate alkalinity in it has an equilibrium pH of 8.0-8.2. That's a very large difference and your pH will always want to rise. Most waters in the US will be quite stable between 7.6-7.8. So, you should look to target your CSI based on where your water's pH wants to be or else you will find yourself in a constant yo-yo battle between lowering pH and then exhausting your alkalinity only to have to add it bake with baking soda additions. You really don't want to be constantly adding acid and baking soda just to achieve some fictitious "optimal pH" value.
As for which is better, pH or CSI, that's a false choice. pH is a component of CSI and, if you keep your CSI balanced, then it doesn't matter what your pH is...the water is balanced, period, full-stop. CSI is a mathematical expression of the saturation of calcium carbonate in pool water relative to what it's theoretical value is based on current pH, TA, etc. So, when your CSI is negative, that means that there slightly less calcium in the water than what the water can actually hold. So the driving force is for calcium to remain in the water and for sources of calcium, ie, your plaster, to want to liberate calcium into the water. A positive CSI means that your water is has slightly more calcium in it than what it can theoretically hold and so the calcium that is in the water wants to precipitate out of solution (typically in the form of calcium carbonate scale). A CSI of zero means that there is exactly the amount of calcium in solution that the water can theoretically hold.
However, CSI is an "unstable equilibrium", that is, it's like trying to balance a bowling ball on the tip of pointed stick. As long as you are actively managing the position of the stick, you can reasonably keep the bowling ball balanced. But, there is always a driving force for the bowling ball to want to fall one way or the other. The same is true for CSI - there is no way to perfectly maintain a CSI of 0 without actively correcting pH, TA, etc. It will always tend to go positive (most of the time) or negative (only under certain circumstances).
With that said, CSI only tells you that there is a driving force that exists to push or pull calcium into or out of solution. It tells you nothing about how fast that will happen. Even if the CSI is negative, the reaction rate and etching rates can be so slow that you will never notice or see the effect. The same is true for scaling - the rate can be entirely imperceptible. This is why TFP says that a CSI within in the range of -0.3 to +0.3 is fine - in that range, there is really no significant scaling or etching that will occur. In fact, the data suggests that you would need of very negative CSI, less than -0.7, for many months before any noticeable etching of the plaster would take place. The same is true for scaling - it is typically only seen inside harsh environment such as your pool heater heat exchanger or inside the SWG cell where the CSI can become very positive either due to high heat or high pH.
You will likely find it very difficult to keep your water anywhere near a pH of 7.5 for any length of time without consistent, daily acid additions. Water with carbonate alkalinity in it has an equilibrium pH of 8.0-8.2. That's a very large difference and your pH will always want to rise. Most waters in the US will be quite stable between 7.6-7.8. So, you should look to target your CSI based on where your water's pH wants to be or else you will find yourself in a constant yo-yo battle between lowering pH and then exhausting your alkalinity only to have to add it bake with baking soda additions. You really don't want to be constantly adding acid and baking soda just to achieve some fictitious "optimal pH" value.