"Recommended" ranges

[Jughead]

I suppose pool maintenance is kind of like medicine - different doctors will have different ideas of the right answer. As I'm in the process of converting my new pool fill from tap water to pool water, I've noticed some discrepancies and I want to make sure I'm as right about it as I can be.

The recommended ranges listed on TFP vary somewhat from what Pebbletec told me they recommend. What issues await me if I use one set of numbers over the other? They don't vary greatly, but enough to make me wonder.

pH: TFP - 7.6 to 7.8, PT - 7.0 to 7.4
TA: TFP - 60 to 80, PT 80 to 100
CH: TFP - 350 to 550, PT 200 to 300
CYA: TFP - 40 to 50, PT 20 to 30
FC: PT 1 to 3
LSI: PT -0.3 to 0.3

This group seems incredibly knowledgeable, but I figure the manufacturer across town has some credibility as well. Can anyone help me figure out the ups and downs of these disparate targets? Thanks!

 

[Dirk]

If you follow TFP guidelines, you will have success with your pool. That said, your warranty is with PebbleTec, not anyone else. If there is a problem with your finish, they might ask you to produce records of the pool's chemical "history," or inspect the pool and take their own readings. If your chemistry differs from their recommendations, they could deny a warranty repair. So that is the real dilemma, more so than what the chemistry differences might do to your pool.

One way to go is to attempt to get as close to TFP numbers as possible while still remaining in range of PebbleTec's. So:
FC: 3
ph: 7.4
TA: 80
CH:300
CYA: 30

This would be close enough to TFP guidelines to get you through the PebbleTec warranty period, then switch to TFP numbers when your warranty expires. The above would give you a CSI of -0.14 (TFP's equivalent of LSI) which is a little aggressive for Pebble but well within the acceptable range. LSI will likely be OK, too, but I don't know how to calculate that quickly.

An FC of 3 with CYA at 30 is living' on the edge. You'd have to keep a close eye on the FC and never let it dip below 2. Doing so risks an algae outbreak. Or goose it to TFP recommendations (4-5), since you could quickly adjust FC downward a bit for any sort of PebbleTec inspection, and none's the wiser. Your finish should survive the other differences well enough. What is your warranty, five years?

 

[Jughead]

I’m fairly certain the warranty has been and gone - it was built six years ago and we are the second owners. My concern was more about the long-term effects of keeping it in other ranges than what the manufacturer says. That said, the previous owner‘s maintenance routine seems to have been to occasionally look out the window and make sure the pool was still there. The calcium ring was horrendous and the filters I don’t think had ever been cleaned. The water was trashed, to the point that a drain and refill was part of the purchase contract when we bought the house. It really was a testament to the construction of the pool and the equipment that they held up so well.

If keeping the numbers in the TFP range - especially for calcium, TA, and pH - are going to keep the pool happy then I’m more than happy to use those.

 

[Repe]

Don't stress too much on readings. If readings are somewhere near from recommended you are fine, as long those are most of time over minimums.

 

[Dirk]

Don't stress too much on readings. If readings are somewhere near from recommended you are fine, as long those are most of time over minimums.

That is not recommended TFP advice. TFP recommendations are based on science and the experiences of over 300,000 members. You don't have to make yourself crazy about it (like I do), but the closer you adhere to TFP guidelines, the more successful you'll be, and the longer your finish will last (which has probably already been compromised, so now is the time to come to its rescue).

For example, I inherited a pool, too. The plaster finish was badly scarred and covered by calcium. And I'll bet the ring around the edge tile rivaled yours. The pool was only about four years old at most. I had to replace the finish and blast the tile. Since I took over the pool, almost five years later the finish is still pristine and the edge tile is only now showing a trace of "crust," which is due more to evaporation than a calcium imbalance. TFP works.

So, you left out the detail about the pools age. Ignore PebbleTec numbers and stick with TFP. That's the short answer. Not only will your pool thank you, but if you purchase one of our recommended test kits, and share its test results, TFP guides and experts will help you with any pool problem you could possibly encounter. Of course, if you stick closely to the TFP methods of pool care, your pool problems might be non-existent! (Well, minimal, anyway.)

 

[Repe]

That is not recommended TFP advice. TFP recommendations are based on science and the experiences of over 300,000 members. You don't have to make yourself crazy about it (like I do), but the closer you adhere to TFP guidelines, the more successful you'll be, and longer your finish will last (which has probably already been compromised, so now is the time to come to its rescue.

For example, I inherited a pool, too. The plaster finish was badly scarred and covered by calcium. And I'll bet the ring around the edge tile rivaled yours. The pool was only about four years old at most. I had to replace the finish and blast the tile. Since I took over the pool, almost five years later the finish is still pristine and edge tile is only now showing a trace of "crust," which is due more to evaporation than a calcium imbalance. TFP works.

So, you left out the detail about the pools age. Ignore PebbleTec numbers and stick with TFP. That's the short answer. Not only will your pool thank you, but if you purchase one of our recommended test kits, and share the results, TFP guides and experts will help you with any pool problem you could possibly encounter. Of course, if you stick closely to the TFP methods of pool care, your pool problems might be non-existent! (Well, minimal, anyway.)

What I was just telling is just stay over recommended minimums pool should be fine. Just adjust once week if needed but if sometimes some reading go out of optimum that's not end of world..

 

[Dirk]

What I was just telling is just stay over recommended minimums pool should be fine. Just adjust once week if needed but if sometimes some reading go out of optimum that's not end of world..

Sorry, that's not quite right either, Repe. It's true that staying within the range of values for any given parameter, as per TFP guidelines, can work just fine, a little high or low is OK, as long as you keep in range. And sometimes it's necessary to adjust those guidelines depending on the individual characteristics of your pool and your climate. But it is not always true that once-a-week adjustments are enough. Sometimes FC and pH need adjusting more often. It can depend on the type of pool you have, it's age, where you live, the season of year and many other factors. And you sort of learn all that, and what works, as you get used to your own pool. But when you're first learning TFP methods, it's best to stick to the numbers we recommend, before you start "coloring outside the lines."

I see you're still building your pool. Keep studying here at TFP, and we'll look forward to helping you gain the knowledge you'll need to care for your new pool, and then to go on to help others.

 

[Repe]

Sorry, that's not quite right either, Repe. It's true that staying within the range of values for any given parameter, as per TFP guidelines, can work just fine, a little high or low is OK, as long as you keep in range. And sometimes it's necessary to adjust those guidelines depending on the individual characteristics of your pool and your climate. But it is not always true that once-a-week adjustments are enough. Sometimes FC and pH need adjusting more often. It can depend on the type of pool you have, it's age, where you live, the season of year and many other factors. And you sort of learn all that, and what works, as you get used to your own pool. But when you're first learning TFP methods, it's best to stick to the numbers we recommend, before you start "coloring outside the lines."

I see you're still building your pool. Keep studying here at TFP, and we'll look forward to helping you gain the knowledge you'll need to care for your new pool, and then to go on to help others.

Pool been ready 3y now just not updated yet..
Of course is best keep all readings optimal but I bet most of pool owners don't have time/interest test everyday. Maybe if you are retired and spend most of days home that might be option. Just don't stress too much..

 

[Jughead]

Thank you - the ring has gotten bad again and there’s another blasting in the works for this fall once the weather cools a little bit. I was using the pool store ranges and those were completely out to lunch, especially when trusting their whirligig machine over my basic Taylor kit to establish the numbers in the first place.

I understand the premise that Repe is saying - stay above the minimums just to stay safe, but I also need to strive for a little more precision than that. I am comfortable with the TFP way, and will use those numbers as my targets going forward. Since the last refill is less than 48 hours old the goal now is just to get the pH, TA, CYA, etc to look more like pool water than tap water and then trim the numbers from there.

 

[Dirk]

If you haven't already, read up on CSI (it's a modified version of LSI, just more appropriate for pools). Maintaining that within range is what's going to minimize if not eliminate the build up on the edge tile. Some of that is from evaporation and is unavoidable, but the majority of it is from CSI being out of range.

If you want to avoid, or at least minimize, water exchanges, you eliminate the tabs and keep a constant CYA. That means dosing with only liquid chlorine, or switching to a salt water pool (which is easier than it sounds). If you have high CH in your fill water, you can minimize its build up by using soft water for fill water, which will also lessen or eliminate the need for water exchanges due to high CH (that's how I do it). Just pointing out that there are ways to alter for the better the way you maintain the water, depending on if you're willing to balance time, money and effort a little differently than you have been.

But first things first. Let's get your water balanced within TFP ranges, and then go from there. Add your test kit and model number to your signature, so we know whatcha got. Download and configure the Pool Math app. That'll do all the dosing calc's for you. And if you have any questions about getting to TFP levels, just holler.

 

[Jughead]

Signature block is updated for the TF-100 test kit which I’ve used so far primarily for CH and CYA. I have a basic DPD test kit from the pool store that uses the same reagents for TA and pH so am using that up, along with the DPD tester just to see if I even have chlorine staying in the water while I get the CYA to something above zero.

Latest test numbers this afternoon were:

pH 7.5
TA 140
CH 250
FC 1
CYA 20 or less

After testing I added muriatic acid (7.0 target, Pool Math app calculations) to bring the TA down some more and have the aerator on 24/7 to bring the pH back up so I can repeat the process until the TA is at least down to 100. I also added a half gallon of 12% bleach and another pound of stabilizer (three total since the refill) and will check the CYA in the morning.

The tablets are history other than for vacation periods - liquid diet from here on unless/until we go with a salt system. I’m also looking at soft water options for the fill system, whether an RV type or tapping into the household water.

Of course, we just got a bunch of rain from a monsoon thunderstorm so that probably won’t help me figure out what changed because of me and what changed because of the rain - like I needed a confounding variable in the middle of all of this.

I’m interested in the salt cell approach but I need to get a lot smarter on them to even be able to ask an intelligent question about it. More reading for tomorrow…

 

[duraleigh]

Disregard the rain as you progress. It has very little affect on your pool.

 

[SoDel]

I suppose pool maintenance is kind of like medicine - different doctors will have different ideas of the right answer. As I'm in the process of converting my new pool fill from tap water to pool water, I've noticed some discrepancies and I want to make sure I'm as right about it as I can be.

The recommended ranges listed on TFP vary somewhat from what Pebbletec told me they recommend. What issues await me if I use one set of numbers over the other? They don't vary greatly, but enough to make me wonder.

pH: TFP - 7.6 to 7.8, PT - 7.0 to 7.4
TA: TFP - 60 to 80, PT 80 to 100
CH: TFP - 350 to 550, PT 200 to 300
CYA: TFP - 40 to 50, PT 20 to 30
FC: PT 1 to 3
LSI: PT -0.3 to 0.3

This group seems incredibly knowledgeable, but I figure the manufacturer across town has some credibility as well. Can anyone help me figure out the ups and downs of these disparate targets? Thanks!

Pebbletec ongoing maintenance recommendations recognize following the LSI and allow for balancing all LSI parameters as long as resulting LSI stays in the range of low probability of etching or scaling (-0.3 to +0.3). Many folks (including me) use TA much lower than the suggested range but compensate by raising CH, for example. Pebbletec’s suggested range for TDS is impossible to achieve in a salt water pool. Doesn’t matter — just compensate for slightly increased LSI from high TDS by adjusting the other parameters. PoolMath and a number of other apps will calculate the LSI/CSI for you. I prefer the Orenda app because it allows you to easily play “what if” with all LSI parameters. PoolMath has strength with logging and with “effect of adding” calculations.

“PTI Recommended Acceptable Ongoing Maintenance Ranges are designed for high-performance finishes and not recommended for traditional pool plaster. Individual parameter ranges may be outside the above PTI Ideal Ranges as long as adjustments are made to the remaining parameters to ensure the Langelier Saturation Index remains within the -0.3 and 3.0 range.” (emphasis supplied)

https://pebbletec.com/wp-content/uploads/2022/01/1-PTI-Start-Up-Maintenance-with-Checklist-All-Finishes-1.20.22.pdf

 

[gingrbredman]

I bet most of pool owners don't have time/interest test everyday

I would agree that most pool owners do not have the interest to keep up on the TFP way. While TFP has more than 300k members, there has to be a lot more pool owners out there, a lot of them hanging around FB groups, or Redit, and have little cares in the world. But the members here, those who really do have interest go about it in a different way than most pool owners. I like being different than most pool owners.

Maybe if you are retired and spend most of days home that might be option

I work a crazy amount of time, have a family, hobbies, home, and pool, and yet find the time to make sure to find the time to keep my pool TF. It does not take being retired or at home to be successful at this, it really is trouble free once you dial it in.

Just don't stress too much

Right on! Like I said, once you dial it in, understand the numbers, and have the right supplies on hand, there is little stress to this at all. The stress comes from new members who have gotten bad advice, trying to understand differences, and see why their pool isn't as awesome looking as all those around here.

@Jughead, nice work with the new test kit and the approach. As you already saw, first priority is to get that chlorine up and keep it there. No need to let it drop and let algae creep in. You will need to keep adding each day, and as your CYA is low, it will be harder, I image in AZ now, the sun is eating up to 5ppm of chlorine per day. With just under a 12k gallon pool, the Pool Math app will tell you how much chlorine to add each day to get to, and stay with the TFP numbers.

 

[Dirk]

Signature block is updated for the TF-100 test kit which I’ve used so far primarily for CH and CYA. I have a basic DPD test kit from the pool store that uses the same reagents for TA and pH so am using that up, along with the DPD tester just to see if I even have chlorine staying in the water while I get the CYA to something above zero.

Latest test numbers this afternoon were:

pH 7.5
TA 140
CH 250
FC 1
CYA 20 or less

After testing I added muriatic acid (7.0 target, Pool Math app calculations) to bring the TA down some more and have the aerator on 24/7 to bring the pH back up so I can repeat the process until the TA is at least down to 100. I also added a half gallon of 12% bleach and another pound of stabilizer (three total since the refill) and will check the CYA in the morning.

The tablets are history other than for vacation periods - liquid diet from here on unless/until we go with a salt system. I’m also looking at soft water options for the fill system, whether an RV type or tapping into the household water.

Of course, we just got a bunch of rain from a monsoon thunderstorm so that probably won’t help me figure out what changed because of me and what changed because of the rain - like I needed a confounding variable in the middle of all of this.

I’m interested in the salt cell approach but I need to get a lot smarter on them to even be able to ask an intelligent question about it. More reading for tomorrow…

You're doing great. Keep that FC up. It's better to overshoot a little on that. You can safely swim in a pool with FC at SLAM level, so a few extra FC points to fight off that AZ sun is going to be perfectly fine. You don't want to get into trouble with algae, so play it safe until you're more confident about how much chlorine your pool is consuming a day, and so how much to add each day.

Run TA and CH tests on your fill water. That will help you (and us) strategize. If you have high CH in your fill, you can leave your current CH as is, as it will accumulate fast enough from all the refilling you're doing to keep up with the AZ evaporation. Let that happen until you decide about the softener. I connected my pool's auto-filler to my home's water softener, and that has worked great. I have a small family, so the softener can keep up with us and the pool's needs no problem. YMMV. If you can rangle a hose from a soft water spigot to fill your pool, you might try that out first before you make any permanent connection or buy a separate unit. See if your softener can keep up. If it can, then that's one less thing to buy and manage. Mine regen's every few days. Not quite sure of the frequency, but I know it's not every day. So that means it's keeping up with demand. I only fill it with salt a few times a year, so that's ezpz. But hold off on that until refilling from your existing fill source brings your CH up to where you want it. Might as well let that happen for free!

Sounds good on the TA plan. That'll help stabilize the pH, too.

Regarding LSI v CSI, that's up to you. I'm not even sure how different those numbers would be. If it were me, I'd calculate CSI (Pool Math does that automatically), and then I'd calculate LSI, and see how off they are from each other. If close enough, I'd target a CSI as close to zero as possible (assuming LSI would also be near zero), and then just use CSI (because Pool Math makes that easy). See what I mean? Don't stress the difference. If I remember my "learnin's," LSI was originally developed for monitoring deposits in concrete pipes used by some industry (can't remember). Something like that. CSI is a modification of the same math, developed to be more appropriate for pools. I bet @JoyfulNoise would be able to fill in my blanks on all that.

Regarding SoDel's advice about PebbleTec and LSI and TDS and PTI and A-B-C, as-simple-as-Do-re-mi, etc, not sure what all that means! And something about an "Orenda app?" I don't know what that is. He's found a system that works for him. Everyone here does the same. So I'll just share what has worked for me (and what I recommend):

When I first moved in to this house with a pool, I got into mixing and matching pool maintenance advice from multiple sources: pool guy, pool store, online, and of course my own logic about it. That just didn't work. It wasn't until I settled on TFP and ignored all others that my pool righted itself. I learned early on to pick one source of advice, and stick with that. Mixing and matching just didn't work. And I certainly wouldn't mix and match pool chemical calculators. TFP's has been very carefully vetted over hundreds of thousands of pools, over many years. That's good enough for me... and it's all in one place.

 

[SoDel]

I should have linked the apps.

Pool Math by TroubleFreePool by TroubleFreePool

PoolMath makes swimming pool care, maintenance and management easy by tracking chlorine, pH, alkalinity and other levels to help calculate how much salt, bleach and other chemicals to add

appadvice.com

The Orenda Calculator®

The Orenda Calculator gives water chemistry dosing instructions along with real-time LSI readings. Try our website version of our calculator here.

www.orendatech.com

LSI and CSI are essentially the same, an index of calcite saturation. Both PoolMath and the Orenda calculators have updated the original LSI methodology by interpolating between the original table values when calculating the index, and automatically calculating carbonate alkalinity from TA accounting for CYA and pH. I can’t remember what else got baked into PoolMath’s CSI (I vaguely remember a mention of a slight change in the TDS coefficients), but for practical purposes, LSI and CSI are interchangeable.

Both TFP and Orenda methodologies recommend managing LSI/CSI to keep the water chemistry balanced. No mix & match. It’s like the difference between using a spreadsheet versus a calculator. Each has benefits and they both get 4 for 2+2.

 

[SoDel]

Also, as better explained than I can, @chem geek pointed out that ‘. . . the derivation of the Langelier Saturation Index has absolutely nothing to do with boilers, closed systems, cast iron corrosion, or any other such nonsense. It is a chemical equilibrium equation solution for the saturation point of calcium carbonate, nothing more. So please stop perpetuating this falsehood that gets repeated over and over again by many in the industry that somehow because Langelier wasn't looking at pools that his equation somehow doesn't apply. That is simply not true at all.”

Pool Water Chemistry

Thanks JasonLion. Maybe the page could say "the range should be 7.5 to 7.8 with 7.7-7.8 being ideal". Then someone would need to offer a suitable pH kit of course: cresol red covers the required range. Extensive experience is important, but there is probably very little experience (let alone...

www.troublefreepool.com

 

[Dirk]

I should have linked the apps.

Pool Math by TroubleFreePool by TroubleFreePool

PoolMath makes swimming pool care, maintenance and management easy by tracking chlorine, pH, alkalinity and other levels to help calculate how much salt, bleach and other chemicals to add

appadvice.com

The Orenda Calculator®

The Orenda Calculator gives water chemistry dosing instructions along with real-time LSI readings. Try our website version of our calculator here.

www.orendatech.com

LSI and CSI are essentially the same, an index of calcite saturation. Both PoolMath and the Orenda calculators have updated the original LSI methodology by interpolating between the original table values when calculating the index, and automatically calculating carbonate alkalinity from TA accounting for CYA and pH. I can’t remember what else got baked into PoolMath’s CSI (I vaguely remember a mention of a slight change in the TDS coefficients), but for practical purposes, LSI and CSI are interchangeable.

Both TFP and Orenda methodologies recommend managing LSI/CSI to keep the water chemistry balanced. No mix & match. It’s like the difference between using a spreadsheet versus a calculator. Each has benefits and they both get 4 for 2+2.

Roger that. I use CSI to monitor what is going on with my pool chemicals relative to the potential of scaling on my finish, my tile and the plates inside my SWG. That's really the take away here. I manipulate my pH to compensate for the other chemical levels in my pool, primarily the creeping CH, but also salt and CYA and water temp, etc, that all can move around during the year and affect scaling to some degree. By keeping my CSI between -0.3 and 0.0 year-round, I've found that scaling is kept to a bare minimum. Some times that means a little lower pH, other times that means a little higher. I keep CSI a bit negative because of the SWG (that's a TFP recommendation). Before I had one, I would try to keep CSI as close to zero as possible.

And I know this is sound, because when I inherited the pool, and before me nobody was even thinking about CH and CSI, my pool and tile were completely caked. So I have direct evidence, at least in my pool, that TFP works, and controlling CSI works.

Also, as better explained than I can, @chem geek pointed out that ‘. . . the derivation of the Langelier Saturation Index has absolutely nothing to do with boilers, closed systems, cast iron corrosion, or any other such nonsense. It is a chemical equilibrium equation solution for the saturation point of calcium carbonate, nothing more. So please stop perpetuating this falsehood that gets repeated over and over again by many in the industry that somehow because Langelier wasn't looking at pools that his equation somehow doesn't apply. That is simply not true at all.”

Pool Water Chemistry

Thanks JasonLion. Maybe the page could say "the range should be 7.5 to 7.8 with 7.7-7.8 being ideal". Then someone would need to offer a suitable pH kit of course: cresol red covers the required range. Extensive experience is important, but there is probably very little experience (let alone...

www.troublefreepool.com

Ah, thanks for the clarification. I knew I was remembering it wrong, at least in part. But I was close about the notion that CSI (at least how TFP calculates it) is more appropriate for pools. Or maybe I should have said more appropriate for TFP methods?

 

[SoDel]

Roger that. I use CSI to monitor what is going on with my pool chemicals relative to the potential of scaling on my finish, my tile and the plates inside my SWG. That's really the take away here. I manipulate my pH to compensate for the other chemical levels in my pool, primarily the creeping CH, but also salt and CYA and water temp, etc, that all can move around during the year and affect scaling to some degree. By keeping my CSI between -0.3 and 0.0 year-round, I've found that scaling is kept to a bare minimum. Some times that means a little lower pH, other times that means a little higher. I keep CSI a bit negative because of the SWG (that's a TFP recommendation). Before I had one, I would try to keep CSI as close to zero as possible.

And I know this is sound, because when I inherited the pool, and before me nobody was even thinking about CH and CSI, my pool and tile were completely caked. So I have direct evidence, at least in my pool, that TFP works, and controlling CSI works.

Ah, thanks for the clarification. I knew I was remembering it wrong, at least in part. But I was close about the notion that CSI (at least how TFP calculates it) is more appropriate for pools. Or maybe I should have said more appropriate for TFP methods?

The LSI vs CSI debate goes back a long way and the history isn’t really interesting (but has been a peeve of mine because I started with LSI so there’s some Ford vs Chevy there lol). I think there’s a strong dose of “not invented here’ in many TFPer’s dismissal of LSI when the reality is the difference between LSI and CSI is generally so trivial as to be non-existant. There are a ton of places where the TFP way really is, by far, by leaps and bounds, the best way. LSI vs CSI just isn’t one of them .

For a personal opinion, I don’t think CSI is any better for pools than LSI; it might be a better way to more perfectly calculate exact calcite saturation equilibrium, but perfect isn’t always practically better, and it might not be perfect or even better anyway, just slightly (ever so slightly) different.

Maybe like if you said your pH is 7.53 and I said my pH is 7.5. What’s the practical difference? Same thing

 

[Dirk]

The LSI vs CSI debate goes back a long way and the history isn’t really interesting (but has been a peeve of mine because I started with LSI so there’s some Ford vs Chevy there lol). I think there’s a strong dose of “not invented here’ in many TFPer’s dismissal of LSI when the reality is the difference between LSI and CSI is generally so trivial as to be non-existant. There are a ton of places where the TFP way really is, by far, by leaps and bounds, the best way. LSI vs CSI just isn’t one of them .

For a personal opinion, I don’t think CSI is any better for pools than LSI; it might be a better way to more perfectly calculate exact calcite saturation equilibrium, but perfect isn’t always practically better, and it might not be perfect or even better anyway, just slightly (ever so slightly) different.

Maybe like if you said your pH is 7.53 and I said my pH is 7.5. What’s the practical difference? Same thing

Agree. I was counting on the notion that LSI and CSI are so close that in terms of the OP's learning curve, and practical application of TFP methods, that if he sticks with Pool Math and uses its automatic CSI calculator, that he'll be just fine, so no need to look elsewhere to control his scaling problem.