Calcium Hardness

[Tman122]

If it Ain't Broke

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  Re: Calcium hardness low
Reply #5 - Today at 4:29am      I have yet for someone to tell me why Calcium Hardness is important?? I know that in concrete/masonary type pools and spas if your water is low in CA it will precipitate it from those type of surfaces ruining them over time. But PVC ,Acrylic and SS heating elements have no calcium to precipitate??? So, I need someone to tell me why CA is important in a modern Hot Tub? If theres a logical reason for it's importance I will start worring about it more and reccomending it's importance more to my customers.  

Wanted to move this to the top as I don't seem to be getting any responses.

[tony]

Roger

I agree.  There is no need to raise calcium hardness in a spa.  I never added calcium until recently.  My dealer also agrees there is no need.  I now raise it only to 100 to give my water a little more polish.  Don't even know if it really does that.

[Tman122]

Roger

I agree.  There is no need to raise calcium hardness in a spa.  I never added calcium until recently.  My dealer also agrees there is no need.  I now raise it only to 100 to give my water a little more polish.  Don't even know if it really does that.

I think we may have talked about this before Tony? I'm kinda suprised we don't get much more out of some of the more weathered water guru's. I had some old time plumber tell me it was not needed in a modern tub as there was nothing that the water could precipitate calcium from. Now hard water may be a different issue as the build up from the excessive calcium may be of more importance, and when you truely think about it in that fashion, one would think you would never want to add calcium to your water as it can build up on plumbing and the like???  

[NE-Phil]

For what's it's worth, I'm interested on hearing some other opinions about this. I bought 5 lbs of calcium hardness plus and have been using to raise it as necessary.

If it's not necessary, I would really not have to buy it.

Anybody else want to chime in?

Phil

[galen]

I buy my chem's from Hotsprings and I have never had to jack with the calcium. I don't know if it has anything to do with what type of chemical your using.

[anne]

So why is it that dealers/etc are so quick to strongly advise against filling a tub with softened water? Is it the sodium, or other ions used to soften the water, or is it  the lack of minerals other than Ca that are a problem?

Funny that we have two nearly identicel threads going  now........

[Tman122]

So why is it that dealers/etc are so quick to strongly advise against filling a tub with softened water? Is it the sodium, or other ions used to soften the water, or is it  the lack of minerals other than Ca that are a problem?

Funny that we have two nearly identicel threads going  now........

It's my fault we have 2 threads going, but it's because I want to find more information on this. I had a customer I was doing a set up for, he bought a Sundance Spa, part of my setup includes a water balance and overview. The Sundance store people said his warranty would be void if I did not maintain his CA it was low out of the tap I think 30-50 I told him I didn't think it was important but he insisted as Sundance insisted but he did ask me why I though it wasn't important and he concured. The dealer could not give him a reason why adding Calcium was so important other than "because" sorry but that seems kinda lame to me. As far as the softened water here and I have heard this in alot of parts of the country we use half softened and half not softened. But very few people in this area even have softeners. I don't. But your right maybe it has some other function, CA I mean. Wheres this Vermonter guy!!

[tony]

Now I have a Sundance spa with low calcium out of the tap (50) and my dealer said no need to bother with adding calcium...not needed unless having water quality problems.  As I mentioned earlier, I am experimenting a litlle by adding to the very low end of "normal" to see if it adds a little polish to the water...something I heard of somewhere along the way.

For those who follow Vermonter's and Northman's routines, Northman discusses his views regarding calcium in his instructions.  He has the same view as Roger, there is no need for adding calcium to todays portable spa.  Calcium is really needed in concrete pools and spas.  BTW, I don't add calcium to my vinal lined pool either and I've got to say, the water in that is spectacular with very little care...

[hottubdan]

I am not a chemist, so forgive me if what I say is not totally exact.

2 reasons for calcium hardness:

1.  Soft water foams.  Often foaming issues are really soft water issues, not from lotions, soaps, etc.

2.  You Taylor Test Kit fans should know this one (unless they have changed their instructions and support documents).  Water balance is the relationship of at least 4 factors, temperature, pH, TA and Calcium Hardness.  If your hardness is low, then, according to the Langlier (sp?) index the industry uses, your pH and TA have to be adjusted accordingly.  pH bounce could be the result, as you would think your TA is in range, but it really isn't.

Does this begin to answer the question?

[tony]

I am not a chemist, so forgive me if what I say is not totally exact.

2 reasons for calcium hardness:

1.  Soft water foams.  Often foaming issues are really soft water issues, not from lotions, soaps, etc.

2.  You Taylor Test Kit fans should know this one (unless they have changed their instructions and support documents).  Water balance is the relationship of at least 4 factors, temperature, pH, TA and Calcium Hardness.  If your hardness is low, then, according to the Langlier (sp?) index the industry uses, your pH and TA have to be adjusted accordingly.  pH bounce could be the result, as you would think your TA is in range, but it really isn't.

Does this begin to answer the question?

The soft water foaming reason is what I am calling adding polish to the water.  That is why I am adding calcium to my water now, but frankly, I don't see a difference.  You are correct regarding the Langlier Index, but to be honest, I played with that early on and found it too burdensom.  To be really correct, you need to adjust for CYA also.  IMO, keeping it simple works best meaning keep you pH, TA, etc in range.  As I said my TA works best in the low range.  When it gets high my pH starts to rise.

[Tman122]

Good discusson keep em coming.

[Tman122]

What do we have so far,

1. Calcium Hardness needs to be treated as a seperate balance issue, than metals in your water. Sequestering agents, used before any mineral purifiers are added (n2) and rinse your filter after allowing them to work for 24-48 hours.

2. Calcium Hardness may or may not help with foaming (if you have a problem with foaming) I still think if you keep what causes foam out of your water, this shouldn't be an issue.

3. Calcium Hardness is part of the overall water balance and may or may not effect PH and TA?? This could be true but the KISS approach seems to work for alot of folks.

4. Does low Calcium Hardness allow for or enduce precipitation from any componets of a modern Hot Tub.......beats me but I dout it. Stainless Steel (heater)...No, PVC (plumbing)....no, but a brittle issue came up, Acrylic (shell surface)....no??

5. Does Calcium Hardness period, contibute to build up on components (scale)....beats me.

So I guess we are getting somewhere but not to far, at this point I still will leave it out of my water care plan for myself and those whom I recomend to.

[Repeat_Offender]

Not sure of the vaidity of this but it comes from my owners manual:

"Low CH can stain the spa surface as well as cause
corrosion to the spa and it's equipment. To correct low CH,
add a CH Increaser. High CH (hard water) can cause cloudy
water as well as rough scale build-up on the spa surface."

[Tman122]

Now we really need a water guy....corrosion, low calcium....how?....Help??

[Bama]

Calcium or not to calcium, this is the question?

Initial filling of my spa, the calcium is low, right.  So, I go to my pantry and throw in 1/2 teaspoon of Dolomite.  Dolomite is calcium without the typically added magnesium.  Magnesium may have been ok, since it is a solvent.
Nutritional lesson here....
Make sure to take at least half the amount of magnesium as you do calcium or to protect yourself from kidney stones.
Ok, calcium is hard, that's good for your bones, but is it good for my tub?
 I don't want it in my tub... am I wrong?