Pool Math vs National Swimming Pool Foundation Range Variance

[Nuhi.Zhuta]

Hello. I am wondering why the variance in ranges between the Pool Math app and the National Swimming Pool Foundation (NSPF)? I’m trying to understand the logic, not trying to sharpshoot. I’ve noted the differences below, and I’m interested in why TFP makes the different recommendation levels. I’ll put TFP values first. Thanks

FC: 3.0-7.0 ppm; 1.0-5.0 ppm (I think I understand why here. Because TFP utilizes CYA levels to determine a more accurate FC level.)
pH (Recommended/Ideal): 7.2-8.0/7.6-7.8;7.2-8.0/7.4-7.6 (With human eyes being in the range of 7.5, I would think that the NSPF ideal ranges would be a better range.)
TA (Recommended/Ideal): 50-90/60-80 ppm; 60-180/80-100 ppm (I would think the slightly higher values would provide a better buffer system)
CH(Recommended/Ideal): 0-650/50-550 ppm; 150-1000/200-400 ppm (I read that low and high calcium levels can have a negative impact to a pool. I am wondering if NSPF recommended is a better ideal range?)
CYA: 30-60/40-50 ppm; N/A/30-50 ppm (Only reason why I even put this in is that my pool is currently at 35 ppm. Should I raise raise to 40?)

 

[kimkats]

TFP's levels are based on science and lots to trial and error. Here is a good link to show the whys of TFP levels:

Pool Water Chemistry

This thread presents my findings so far on pool water chemistry including the following: More Accurate Calcite Saturation Index (CSI) to replace Langelier Saturation Index (LSI) Calculation of ppm HOCl (disinfecting chlorine) at various levels of Total Free Chlorine (FC) and Cyanuric Acid (CYA)...

www.troublefreepool.com

 

[cowboycasey]

Chem Geek was/is all over this and knows his stuff

 

[Leebo]

FC-Youve got it right, other outside of TFP tend to ignore the FC/CYA ratio. To keep a pool “clean” they tend to suggest other products like algaecides to assist chlorine. Often these products are either costly or have other side effects.

pH and TA- Rather than typing, let me play a video

CH- There’s a fair amount of flexibility here, and they tend to use some of that wiggle room. That said we tend to suggest keeping ours lower to prevent scaling on a SWG. All honesty, there are some who go well above the 650ppm levels we suggest, but they pay close attention to their CSI to avoid scale. As a whole it’s easier for the large majority to just keep CH below 650

CYA-I’m actually shocked that’s their recommendation. I kinda figured they’d suggest higher to allow for pucks to be more commonly used. Brings a smile to my face! That said, I’d say it’s beneficial to increase your CYA, but that doesn’t mean just run out there and dump some in. Instead, use it to your advantage and maybe use pucks for awhile while also paying attention to your CYA.

 

[AUSpool]

The average pH of sea water is 8.3. Ive never had problems with my eyes in sea water. The industry standard for pH is set at 7.6 assuming no cyanuric acid.

A high TA is only useful when your water has a tendency for acidification. While TA will buffer against acidification it does little to prevent a rise in pH which tends to occur with a SWCG. Natural waterways have a TA of ~20ppm TA.

I don’t know what a hydropool chlorinator is but if it is any type of standard salt water chlorinator you will benefit from a CYA an 70-80ppm. Tried and proven by yours truly.

 

[Nuhi.Zhuta]

It is a chlorine system. I am interested in transitioning to a SWG, but planning to make that change after some more research. Also, I’ve spent a good amount of money on the pool/home as a first year home owner. So, am going to plan for it as a future expense.

 

[AUSpool]

It is a chlorine system. I am interested in transitioning to a SWG, but planning to make that change after some more research. Also, I’ve spent a good amount of money on the pool/home as a first year home owner. So, am going to plan for it as a future expense.

From what I can tell from google your Hydropool inline chlorinator is trichlor tablet feeder. Tablets are nicely explained in Leebo’s post above. They add chlorine, or bleach, which is used up for sanitation and ‘burned off’ or degraded by the sun. But they also add cyanuric acid, CYA or stabiliser, which remains behind in your pool and the concentration builds up. Somewhere way down on the bottom of you bucket of tabs will be a tiny little line that says “do not exceed 100ppm of cyanuric acid”. Once you go over 100ppm CYA any amount of pucks or super chlorinating slowly becomes ineffective and your pool starts to go green. The pool store will sell you algacides, shock and floculants and eventually tell you to drain your pool and start again.

CYA: 30-60/40-50 ppm; N/A/30-50 ppm (Only reason why I even put this in is that my pool is currently at 35 ppm. Should I raise raise to 40?)

NO. If you’ve been chlorinating with pucks your probably already over 40ppm of CYA. Time to switch to regular bleach or liquid pool chlorine which is just a more concentrated form of regular bleach.

But you do want to monitor you CYA and maintain it at 40-50ppm. Using bleach you will notice your pH may start to slowly rise and you’ll need to start using muratic acid. Don’t be tempted with the dry acid.

Your Taylor K2005 is a good kit but it does not have the FAS DPD FC test. You can get this separately and I would highly recommend the speedstir.

 

[KevJB]

I wrote Taylor, asking specifically, about the TFP CYA 70-80 vs. the 30-50 industry standard. I am more concerned about the CYA metric as it is difficult to remove if too high. I received a rather scathing response that summarized the lack of acceptable science to support the various high CYA level theories. Taylor’s bottom line, from a high level employee, said 70-80 is too high. On the other end of the expert spectrum, Orenda Technologies recommends a low CYA level to avoid over-stabilization. Both have compelling arguments.

Water balance is another metric I want to get right along with sanitation. Concerning the LSI/CSI saturation index, both the TFP and Orenda calculators match exactly with my measured results. The Taylor Watergram wheel, included with my test kit, requires me to use a CYA factor for TA. It appears that the Watergram wheel uses an ”adjusted” TA - not an absolute value of TA. I prefer the calculators over the wheel because they are easier to use. Bottom line - I feel comfortable monitoring my LSI.

I am new to all of this and my pebble pool is less than a year old. I don’t have a four foot forehead to critique Chemgeek, Taylor, Orenda, or anyone else. I’m neither qualified or invited. I am very frustrated with how difficult it is to determine which “expert” is correct. The consequences of an incorrect choice can be severe, especially for a pebble finish. I will have to keep researching and make that determination myself. I use Taylor test kits to test chemicals and salt and trust my results over others. I am using Taylor recommended values which the pool installer uses and don’t want to invalidate my warranty. The water is crystal clear. No scaling or etching. I just need to get the CYA value dialed in and be done with it!

 

[cowboycasey]

I wonder what they think about pools that use pucks that are over 100 to 200 CYA, I guess that is "ok" since they are using pucks and not a SWG...

 

[magiteck]

I wrote Taylor, asking specifically, about the TFP CYA 70-80 vs. the 30-50 industry standard. I am more concerned about the CYA metric as it is difficult to remove if too high. I received a rather scathing response that summarized the lack of acceptable science to support the various high CYA level theories. Taylor’s bottom line, from a high level employee, said 70-80 is too high. On the other end of the expert spectrum, Orenda Technologies recommends a low CYA level to avoid over-stabilization. Both have compelling arguments.

Water balance is another metric I want to get right along with sanitation. Concerning the LSI/CSI saturation index, both the TFP and Orenda calculators match exactly with my measured results. The Taylor Watergram wheel, included with my test kit, requires me to use a CYA factor for TA. It appears that the Watergram wheel uses an ”adjusted” TA - not an absolute value of TA. I prefer the calculators over the wheel because they are easier to use. Bottom line - I feel comfortable monitoring my LSI.

I am new to all of this and my pebble pool is less than a year old. I don’t have a four foot forehead to critique Chemgeek, Taylor, Orenda, or anyone else. I’m neither qualified or invited. I am very frustrated with how difficult it is to determine which “expert” is correct. The consequences of an incorrect choice can be severe, especially for a pebble finish. I will have to keep researching and make that determination myself. I use Taylor test kits to test chemicals and salt and trust my results over others. I am using Taylor recommended values which the pool installer uses and don’t want to invalidate my warranty. The water is crystal clear. No scaling or etching. I just need to get the CYA value dialed in and be done with it!

If it makes you feel better, you can probably run your SWG with a CYA of 30-50, and set your SWG output higher to account for the increased daily loss. As long as you can keep your FC above the minimum it's not going to hurt anything. You will, however, have to generate a higher amount of chlorine to keep up, which will in turn shorten the life of your cell.

 

[HermanTX]

If it makes you feel better, you can probably run your SWG with a CYA of 30-50, and set your SWG output higher to account for the increased daily loss. As long as you can keep your FC above the minimum it's not going to hurt anything. You will, however, have to generate a higher amount of chlorine to keep up, which will in turn shorten the life of your cell.

This is well stated. TFP provides excellent guidance to balance proper chemistry with economical solutions.

 

[poolnovice1]

Hello. I am wondering why the variance in ranges between the Pool Math app and the National Swimming Pool Foundation (NSPF)? I’m trying to understand the logic, not trying to sharpshoot. I’ve noted the differences below, and I’m interested in why TFP makes the different recommendation levels. I’ll put TFP values first. Thanks

FC: 3.0-7.0 ppm; 1.0-5.0 ppm (I think I understand why here. Because TFP utilizes CYA levels to determine a more accurate FC level.)
pH (Recommended/Ideal): 7.2-8.0/7.6-7.8;7.2-8.0/7.4-7.6 (With human eyes being in the range of 7.5, I would think that the NSPF ideal ranges would be a better range.)
TA (Recommended/Ideal): 50-90/60-80 ppm; 60-180/80-100 ppm (I would think the slightly higher values would provide a better buffer system)
CH(Recommended/Ideal): 0-650/50-550 ppm; 150-1000/200-400 ppm (I read that low and high calcium levels can have a negative impact to a pool. I am wondering if NSPF recommended is a better ideal range?)
CYA: 30-60/40-50 ppm; N/A/30-50 ppm (Only reason why I even put this in is that my pool is currently at 35 ppm. Should I raise raise to 40?)

I *think* TFP sees it as a balancing act, whereas NSPF looks at the individual parts. For example, you can have lower or higher PH as long as TA and CH levels are at their appropriate levels in relation to your PH level (CSI or LSI saturation). On the flip side, you can have everything at ideal NSFP ranges and your pool can still be not balanced per CSI or LSI.

In addition, there might be a practicality component to it. I can tell you from experience that a PH of 7.4-7.6 and TA of 80-100 is impractical, at least for my pool. I would need to add muriatic acid daily and baking soda every other day to keep it there. However, at a PH of 8.0 and TA at 50, I can get by with weekly dosage.