I'm seeing different recommended levels for CH in a vinyl pool?

rawb

Bronze Supporter
May 3, 2017
144
0
Lexington, SC
#1
I'm seeing things like "220 to 350ppm, vinyl lower" on TFP. Also seeing in the ABC's of Pool Chemistry that calcium technically isn't even needed for vinyl pools. My PB is recommending about 200 for my vinyl pool. Wondering why I'm seeing so many different recommendations :) Right now I'm at 175. Thoughts?

Thanks!
 

JoyfulNoise

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TFP Expert
May 23, 2015
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Tucson, AZ
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#2
Because calcium, as far as the limited science goes, is not a factor for the vinyl surface. So, the reason to add calcium to a vinyl pool is for bather comfort, controlling foaminess and equipment safety. If you consider only those factors, then CH can be as low as 150ppm for foaming water control and as high as 350ppm for pool heater care.

If you target a CH if 200ppm and keep your other parameters within TFP recommended levels, your pool will be fine.
 

rawb

Bronze Supporter
May 3, 2017
144
0
Lexington, SC
#3
OK..that sounds great! I don't have a heater currently and may never have one. So in the absence of that, would you still recommended shooting for the 200 mark in general?
 

JoyfulNoise

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May 23, 2015
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Tucson, AZ
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#4
How much rain dilution do you get? 200ppm is a perfectly fine place to start. Since you don’t have a heater then all you need to care about is the water getting foamy. Once CH is above 100ppm, foam really isn’t a problem. So, if you get a good amount of rain dilution that drives your CH down over the season, I’d just dose the pool once with calcium to get the CH up such that you don’t have to add any the rest of the summer. Let it drift down towards closing.
 

PoolguyinCT

In The Industry
Jul 22, 2014
2,658
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Connecticut
#5
Because calcium, as far as the limited science goes, is not a factor for the vinyl surface. So, the reason to add calcium to a vinyl pool is for bather comfort, controlling foaminess and equipment safety. If you consider only those factors, then CH can be as low as 150ppm for foaming water control and as high as 350ppm for pool heater care.

If you target a CH if 200ppm and keep your other parameters within TFP recommended levels, your pool will be fine.
Some mainstream vinyl has been tested to contain 20 to 25%
Calcium carbonate. It has been used as a “cheap”
Raw filler instead of ample plasticizers.

For years, I was of the opinion that calcium level is secondary in liner pools- I now give it the same attention as plaster finishes..
 

JoyfulNoise

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TFP Expert
May 23, 2015
14,318
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Tucson, AZ
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#6
Some mainstream vinyl has been tested to contain 20 to 25%
Calcium carbonate. It has been used as a “cheap”
Raw filler instead of ample plasticizers.

For years, I was of the opinion that calcium level is secondary in liner pools- I now give it the same attention as plaster finishes..
I’m not doubting the presence of calcium in liners - it’s used very widely to modify the mechanical properties of vinyl which helps with the manufacturing (mixing, thermal control, viscosity, roll processing, etc) and it’s also used as a base white colorant as opposed to the more expensive titanium dioxide. The question is - does aggressive water remove calcium from the vinyl and how does any loss of calcium from the vinyl impact it’s performance and longevity? Those questions only have anecdotal answers and no real science behind them.

I look forward to your up-coming research paper on the topic being accepted by the Journal of Applied Polymer Science....:geek:
 

PoolguyinCT

In The Industry
Jul 22, 2014
2,658
0
Connecticut
#7
The questionable material is “growing/expanding”
, releasing ink & looks like raisin below the waterline.

Traditionally liners have been made with a mere 3% cal.

As for its function that is outside of my purview, clearly I am not a chemist or an academic, I am just a very nosey & curious guy.

The research will likely be industry financed & done by a third party..

& yes antidotal for now, I have seen it a couple times in person. I cringe at the thought of the nuisances this may subject dealers to.

I can’t remember where I read it, but material was removed & gained significant weight. I presume water is the weight.

So keep that calcium up, it’s cheap stuff.
 

JoyfulNoise

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TFP Expert
May 23, 2015
14,318
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Tucson, AZ
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#8
I’ll send you bags of my local soil. It’s heavy clay and caliche. If you want a purer grade, I’ll scrap all the crusty stuff off my faucets and send it to you....all the calcium you could ever want ;)
 
Jun 9, 2015
108
0
Canton, GA
#11
Do you have fiberglass steps or a metal ladder? I wouldn't worry too much about low CH in a vinyl pool, but I don't see how it can hurt to leave it around 200. It's not very expensive, and it's not something you have to pay close attention to.