NEWS ALERT! Calcium Keeps Vinyl Liner From Drying Out...

bassadict69

Well-known member
May 26, 2007
148
Benton, La
...at least that was the pool stores reasoning for instructing me to add some calcium to my vinyl lined AG pool. :roll:

I took a sample today to get it tested to make sure my test kit was ok & that I was coming up with the righ numbers. Calcium was a little low & they wanted me to buy 10 pounds of calcium to bring it up. I told her if she could tell me what the calcium would do to help my pool I MAY buy some. She says, "The calcium keeps the liner from drying out." I asked her "Above or below the water line" but could not wait for an answer before laughing out loud in her face. The manager then got involved in arguing with me about it.

WAHT A JOKE!
 

Buggsw

LifeTime Supporter
Apr 22, 2007
925
Arizona
Boy, I wish I could find this article I was reading yesterday, but it was claiming that calcium is all part of balancing water because it can help with your TA balance. Don't know if it's true. Maybe some of the chemical experts here know something of this.
 

eelhc

Active member
May 30, 2007
39
Just be happy with your pool...

bassadict69 said:
She says, "The calcium keeps the liner from drying out." I asked her "Above or below the water line" but could not wait for an answer before laughing out loud in her face. The manager then got involved in arguing with me about it.
Don't get me wrong... I have no affinity for pool stores in general but...

  • Did you intend to purchase anything at the pool store or did you just want to take their time and use their equipment to verify your results?
    Why not take it easy on the poor minimum wage, seasonal employee who's doing just what she's being told?
    And above all... Why waste time arguing with the pool store people?

A simple no thanks to the stuff you don't need would do. Retail (not just pool stores) is full of stores/people trying to sell you junk that you don't need.

Cheers... Enjoy your pool
 

bassadict69

Well-known member
May 26, 2007
148
Benton, La
Well, lets see...I bought the pool from them, I buy all supplies from them, I was planning to buy some cal hypo tabs yesterday from them but they were out. At the beginning of this season I bout a pump & new vacuum hose from them. So yes, everything I buy from a pool store, I buy from them & have been dealing with them for the 5-6 years I have had my pool.

Why should I take it easy on them? This employee wasn't seasonal, she has been with them for several years.

Selling stuff that people do not need & trying to convince them that they need it is just plain WRONG! I sell parts for a living & would never think of selling someone something they do not need.
 

sunsoaker

Member
Jun 17, 2007
23
Florida
The guy we hired to fix our pool equipment tells me the same thing. I didn't really respond either way since he wasn't trying to sell me anything. He claims the vinyl needs the calcium or it will become brittle over time.
 

eelhc

Active member
May 30, 2007
39
bassadict69 said:
Selling stuff that people do not need & trying to convince them that they need it is just plain WRONG! I sell parts for a living & would never think of selling someone something they do not need.
And they'll never change.... No sense in wasting your time. The best one can do is to educate neighbors/family/friends... Whenever someone I know is having pool water problems I offer to do a full test (usually they're using strips or a simple OTO test) then I recommend what they should be putting in their pool (raises some eyebrows initially but the quality of my water speaks for itself).
 

mikergibson

LifeTime Supporter
Jun 13, 2007
34
Mt. Vernon, Illinois
I was pool stored into buying calcium for my fiberglass pool because I was told that it would etch the fiberglass if I didn't have it in there. My calcium was zero and they sold me on buying a 20 pound bag..
I agree, getting people to buy stuff they don't need is wrong and they need to be called on it once in a while
JMHO

Mike
 

Buggsw

LifeTime Supporter
Apr 22, 2007
925
Arizona
I think, though, anyone with pool heaters does need to keep a certain amount of calcium. I know some heater manufacturers will not honor the warranty unless you have kept your calcium and pH/TA in a particular range.
 

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
12,083
San Rafael, CA USA
It's not the low calcium that makes the water corrosive, but the chlorine itself. Remember that the residual chlorine they are using has no CYA so the disinfecting chlorine level, which determines how fast it oxidizes (corrodes), is VERY high -- about 20 times higher than found in pools. They add corrosion inhibitors to partly offset this and they raise the pH so it is above 7.0. Now they happen to use calcium hydroxide to raise the pH, but could have used sodium hydroxide instead -- they added it to raise pH, not to add calcium (though it does do that, too).

In the water system where I live they do not add any corrosion inhibitors since they no longer use chlorine and instead use monochloramine as the residual. It lasts longer, does not form disinfection by-products, and is less corrosive (it's similar to having chlorine with CYA in terms of oxidation potential). The pH is set to around 8.0 which significantly reduces corrosion potential. The tap water has around 50 ppm Calcium Hardness and does not corrode pipes.

Not having calcium in a pool is not going to corrode metal. It will, however, cause water to dissolve calcium carbonate from plaster/gunite/grout. In practice, almost any fill water is going to have at least a little calcium in it. It just won't be at saturation levels.
 

NWMNMom

TFP Expert
LifeTime Supporter
Apr 8, 2007
1,582
Waaay NW MN
sunsoaker said:
The guy we hired to fix our pool equipment tells me the same thing. I didn't really respond either way since he wasn't trying to sell me anything. He claims the vinyl needs the calcium or it will become brittle over time.
No, vinyl needs WATER or it will become brittle over time. Lol
 

Shelley N

Well-known member
May 1, 2007
199
Denver, Colorado
Show me a vinyl liner over 7 years old that isn't a little brittle. It's the nature of the beast.

I wonder if I add calcium to my deck will it stay fresh and new looking?! :eek: Could be the new miracle cure.
 

Poseidon

Well-known member
May 24, 2007
148
Houston, Texas, USA
I do believe that some calcium is needed for vinyl, but not for the calcium itself, rather to provide a way of making the water less aggressive (I prefer the term "aggressive" as opposed to "corrosive" to eliminate confusion with acidic). Suppose you had "perfect" water, with pH 7.5, TA 100, with water temp say 84º F, but no calcium. That would be extremely aggressive water. What would that do to a vinyl liner? I have no idea. Would it be an irritant to bathers? I have no idea. So, just to be safe, I would add some calcium to make the water less aggressive. It's generally accepted that you can run a higher TA in vinyl. This is to offset the lower calcium. Having said all that, I have (and will continue to) let my calcium reduce itself over time via dilution .... but not completely.
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,879
Silver Spring, MD
Many people run their vinyl liner pools with very low calcium and haven't had any problems. Water without any calcium will leach calcium out of any paster/concrete/grout/tile/pebble surface in constant contact with the water. As long as you don't have any of those you will be fine. A typical vinyl liner pool is just fine without any calcium.
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,879
Silver Spring, MD
I don't believe there is clear evidence either way for acrylic or fiberglass. I imgaine they will be fine and there isn't any quick damage the way there can be on a plaster pool, but I haven't heard of any serious long term testing. Someone else might know.
 
G

Guest

There is some eveidence that calcium is needed for fiberglass to prevent cobalt leaching from the gelcoat and causing cobalt staining but it is very sketchy. The exact level of calcium needed has not been determined to the best of my knowledge and there is conflicting info from different fiberglass manufacturers.