Pool Math vs National Swimming Pool Foundation Range Variance

Nuhi.Zhuta

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Mar 22, 2021
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Angier, NC
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Chlorine
Liquid Chlorine
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

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Jul 10, 2012
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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:
 
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Leebo

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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

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Sep 23, 2015
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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. :)
 
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Nuhi.Zhuta

Member
Mar 22, 2021
7
Angier, NC
Pool Size
26000
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Chlorine
Liquid Chlorine
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.
 
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AUSpool

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Sep 23, 2015
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Brisbane, Australia.
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Salt Water Generator
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.