SWG and Limestone Waterfall

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D

dustindb

0
Aug 2, 2017
32
TX
I'm in Central Texas. The SWG has obliterated our limestone coping and the limestone waterfall has a significant leak. I'll replace the coping with something more resistant but I'm not sure what to do about the waterfall. I'm guessing the leak was caused from a break in the mortar. I don't want to repair it just to have it happen again and it's a nice waterfall so I don't really want to tear it out and start over either. Any ideas?
 
Dustin,

Why do you think it was the saltwater and not just the water??? There is very little salt in a saltwater pool..

While limestone is very pretty, it is not really "stone"... :mrgreen:

Let's see if some of our other members have some ideas on how to protect you waterfall...

Thanks,

Jim R.
 
I've tried maintaining with bleach rather than SWG and there is no degradation. When I go back to salt, the difference is painfully obvious. It just starts chipping away. Previous owners came to the same conclusion. We also have incredibly hard well water.
 
Dustin,

Well that is a puzzle as it make no sense... Even if salt was an issue, it should take years to see any changes and you are saying you can see immediate changes... Very odd indeed.. :scratch:

What city do you live in??

When you take the coping out, would it be possible for your to save me a few pieces.. ??? I'd like to run some experiments.. I'll either come pick it up in person or I'll pay for shipping.

So far we have not been able to find one valid case of saltwater damage..

Would also appreciate pictures of the damaged stone.. Is the damage in one area or all over or ???

Thanks,

Jim R.
 
Dustin,

It is hard for me to tell, but the limestone that is away from the pool, appears to be vertical.. Is that true?

Is your waterfall also made out of this same material?

Let's see if @bdavis466 has any ideas on fixing your waterfall.. I suspect he will want a pic of the damage so he knows what needs to be done..

Thanks,

Jim R.
 

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The two different stones are both horizontal.

The waterfall is limestone, but made of huge stones with mortar. It’s hard to tell exactly where the problem is. It’s leaking out the back, I presume through cracks in the mortar.

108582
108584
 
All you are describing/providing is circumstantial evidence. In order to switch to fresh water, you would have to have emptied most of the pool. This means all of your numbers were changed. No way to know what the numbers were before. pH could have been wildly off. No one knows for sure. But again as said above, we have seen no verifiable cases where saltwater cause any additional corrosion over what freshwater would cause.
 
Okay I didn't want the thread to turn into this but here we are.

I bought the house. The previous owner said they switched to chlorine because the salt eroded everything and it's been fine on chlorine. I researched TFP, etc and concluded that they probably didn't maintain the chemistry correctly and I would try out the SWG. I confirmed salt levels were very low, and added an appropriate amount of salt, etc to set up the SWG. I followed TFP's water balance guidelines, I didn't make any drastic changes.

I didn't expect to see any erosion, and if I did, I didn't think it would be noticeable without a 6 month photo. Very wrong. The rock started chipping up and pebbles/dust began to appear within a month or 2. No before/after photo necessary, very obvious. Maybe it's still circumstantial but I don't know how else to convince you. Maybe it's just an exact formula of my climate and very hard well water.
 
Dustin,

We are just puzzled, as it makes very little sense.. I don't doubt that what you saw, is what you saw, but most things can be proven with some type of test or science.. So far we have been unable to duplicate the problem...

I assume you are using the same hard well water in the pool, be it a saltwater pool or not, so I can't see how that would matter..

If I were in your shoes, I would not be using a SWCG either..

Please let me know when you rip the coping out and I'll come down and pick some up.. Please set aside 4 or 5 square feet if you can.. I understand it will be in pieces.. It is already in pieces... :mrgreen:

As far as the waterfall goes, I would assume you will just have to replace the grout. I'm sure that when BDavis chimes in, he can let us know what the best options are..

Thanks,

Jim R.
 
Know we are learning with you. We have heard "salt=bad for coping" but so far have not seen it. You have our interest This could a big learning experience for all of us! PLEASE keep us up on the details and any more input you might have on what happened and when!
 
Well, the coping damage is pretty evident - the question is, WHAT actually caused the stone to erode in such a way. What is also interesting in the pictures you've provided is that the waterfall also appears to be made of limestone as well as the horizontal pieces of stone sitting beneath the waterfall under the surface, yet neither of them appear to have similar erosion. One may assume if the saltwater is the culprit of the erosion, then the stone on the waterfall and below would also show at least some similar signs. An argument could be made the stone pieces below the surface are not exposed to as much UV or drying as the coping, but the waterfall would be hit by slash-out as well as saltwater running over the surface any time it is on. It is very peculiar there is no obvious erosion of the waterfall stones.

I'm also curious of this "SWCG = stone / equipment damage" as outside of TFP that's about all you hear. I'm also in Central TX (just NW of Austin) and am considering moving from bleach/trichlor to a SWCG primarily for the convenience factor and that I like the feel of saltwater anyway and some seasons bring my salt level to 1500 ppm + just for that reason, so why not? Yet when I call anyone to inquire about quoting install of a SWCG the first question they ask is "why would you want one?" followed by "are you aware of the potential risks for damages" or "we usually do not recommend them". Everything I've read at TFP states these fears and claims are unproven, yet many professionals in the pool industry still claim otherwise. I do have OK flagstone as my coping and spillover from my spa, so that is my only hesitation. However, my friend and neighbor down the street has similar stone and no SWCG, yet his stone is flaking and chipping in multiple areas. Point being, sometimes it is the stone and/or climate more than anything. Perhaps the physical properties of your particular coping, Dustin, is hypersensitive to even the relatively low levels of salt required for a SWCG?

Regardless, it's certainly a disappointment having to go through a renovation process. Hopefully you find a coping material where any such damage is not a concern and you're able to enjoy the benefits of the SWCG you already have.

Will be interesting to hear the results of any testing Jim performs on your coping stone.
 
Limestone is known to have large portions of it comprised of organic matter. If anything is degrading the stone it's the chlorine. It would also make sense why some of the limestone is having issues and other pieces are not.

Most mortars do not hold up well in wet/dry and submerged situations. You might want to look into using an epoxy grout or hydraulic cement.
 
You know if it is the chlorine, it would make sense that a saltwater pool would be more damaging. In most saltwater pools not only are the chlorine levels higher they are also continuous. No dips in the chlorine level to wash the susceptible stone. Not sure that makes sense I am not a chemist. I just find it so hard to believe the 1200 parts saltwater is ok but 3000 parts is not. It just isn't much more salt.
 
Can we blame any of this on poor quality limestone? It just looks like it was full of "faults" to begin with... ? I mean, that stuff just looks porus as all get out. Could this have been poor quality stone from the start and then negatively affected by pH perhaps?

The grout dissolving makes me think none of the coping was done with the right supplies to begin with.

Maddie :flower:
 

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