Natural Rock Damage with SWCG

[Scubaski]

Welcome to the board!

I am quite anxious as well since my husband loves the look of our pools back wall when it is wet, I have considered sealing the rock. We have a salt pool that is being filled as we speak, I look forward to hearing comments as well.

Iam told the salt water pool will eat up the rock copping and water fall my Nieghbor has had this same problem

 

[Jimrahbe]

Iam told the salt water pool will eat up the rock copping and water fall my Nieghbor has had this same problem

S,

That is a load of Bull Feathers.. It is just not true.. Have you ever been to the East or West coast of the US? The ocean water is 10 X times more salty than pool water and I don't see those rocks dissolving.

If the "rocks" you are using for the waterfall are made of sandstone, then any water running over them will cause them to slowly disolve.

Show me pics of any damage to a waterfall caused by saltwater. Show me your neighbor's damage.

Thanks,

Jim R.

 

[joepaiii]

Iam told the salt water pool will eat up the rock copping and water fall my Nieghbor has had this same problem

S,

That is a load of Bull Feathers.. It is just not true.. Have you ever been to the East or West coast of the US? The ocean water is 10 X times more salty than pool water and I don't see those rocks dissolving.

If the "rocks" you are using for the waterfall are made of sandstone, then any water running over them will cause them to slowly disolve.

Show me pics of any damage to a waterfall caused by saltwater. Show me your neighbor's damage.

Thanks,

Jim R.

I will get some pics of my 1 year old waterfall that has damage.

I know the deal here on TFP is that salt couldn't possibly do it. Salt can be part of the issue and I think we need to be sure to tell people to seal their rocks that are near a salt pool. I am positive I see more damage to sandstone type rocks around a salt pool then with pools that don't have salt water.

Unfortunately there is no way to prove any of this one way or another. Unless you take the same stone cut it in half and install it on two pools -one salt and one not in the same weather conditions and see what happens. It could be the stone falls apart for both pools or maybe the one with a salt pool fall apart sooner.

And by the way - sand is literally ground up and broken down rock so not sure the validity of the ocean/shoreline argument.

 

[joepaiii]

S,

That is a load of Bull Feathers.. It is just not true.. Have you ever been to the East or West coast of the US? The ocean water is 10 X times more salty than pool water and I don't see those rocks dissolving.

If the "rocks" you are using for the waterfall are made of sandstone, then any water running over them will cause them to slowly disolve.

Show me pics of any damage to a waterfall caused by saltwater. Show me your neighbor's damage.

Thanks,

Jim R.

These pics show where the water spray from the waterfall is eroding the vertical stone. This is a 1 year old pool. Maybe it would have happened without salt... but I really don't think it would have happened as quickly. I need to get it sealed - why my pool builder didn't seal this vertical rock is beyond me but they didn't and won't with out me paying for it. I have some stonetech that I am going to seal it with... just need to get around to it.

 

[Jimrahbe]

Joe,

It takes millions of years for rock to become sand.. And if saltwater eats sand, why is there any sand left in the ocean at all.. ?

Our take here at TFP is that the problem is the quality of stone and not the saltwater. Like you, my take is based only upon my experience with the stone I have..

Here is my story and I'm sticking to it..

I bought a house with a pool and had flagstone coping installed as well as new tile and plaster. This was about 14 years ago.. At that time I knew nothing of TFP and the pool was a typical chlorine tablet pool. Within a couple of months some of the flagstone started to shed very thin layers of sand.. Some stones did it and some did not and there was no rhyme or reason as to which stones shed and which did not.. A good stone was often right next to a bad stone.. I assumed this was normal.. A couple of years later I converted over to a SWCG and nothing changed.. The bad stones are still bad and the good stones are still good.. The pool has been a saltwater pool for about 9 or 10 years now and the problem is the same.. Granted this is not a waterfall, but the coping gets plenty of pool water splashed on it.. You'd think that there would be more damage at the entry and exit points, but that is just not true.

I see this the same as me saying you beat your wife and everyone assumes it is true unless you can prove differently.. I should not be allow to say you beat your wife unless I can actually prove it.

Thanks for the pics.. They look pretty much like every pic I have seen of a waterfall wall, saltwater or not..

I agree it would be nice if we had some actual test results that we could compare..

I have my doubts that a sealer will do anything, but it certainly can't hurt.

Thanks for your input.

Jim R.

 

[ajw22]

These pics show where the water spray from the waterfall is eroding the vertical stone.

There is no argument that water erodes stone. That is how the Grand Canyon was created. There is no salt in the water that created the Grand Canyon.

Water created the erosion - yes.

Salt creating the erosion - incidental.

 

[joepaiii]

Joe,

It takes millions of years for rock to become sand.. And if saltwater eats sand, why is there any sand left in the ocean at all.. ?

Our take here at TFP is that the problem is the quality of stone and not the saltwater. Like you, my take is based only upon my experience with the stone I have..

Here is my story and I'm sticking to it..

I bought a house with a pool and had flagstone coping installed as well as new tile and plaster. This was about 14 years ago.. At that time I knew nothing of TFP and the pool was a typical chlorine tablet pool. Within a couple of months some of the flagstone started to shed very thin layers of sand.. Some stones did it and some did not and there was no rhyme or reason as to which stones shed and which did not.. A good stone was often right next to a bad stone.. I assumed this was normal.. A couple of years later I converted over to a SWCG and nothing changed.. The bad stones are still bad and the good stones are still good.. The pool has been a saltwater pool for about 9 or 10 years now and the problem is the same.. Granted this is not a waterfall, but the coping gets plenty of pool water splashed on it.. You'd think that there would be more damage at the entry and exit points, but that is just not true.

I see this the same as me saying you beat your wife and everyone assumes it is true unless you can prove differently.. I should not be allow to say you beat your wife unless I can actually prove it.

Thanks for the pics.. They look pretty much like every pic I have seen of a waterfall wall, saltwater or not..

I agree it would be nice if we had some actual test results that we could compare..

I have my doubts that a sealer will do anything, but it certainly can't hurt.

Thanks for your input.

Jim R.

I had a similar experience with my 2nd pool. I agree that this flagstone here in Texas is not very solid rock.

I do know that sealing it does definitely reduce the sandiness and way the rock behaves around salt water. I still believe it breaks down faster around salt water but no way to prove disprove it without some serious controlled experiments.

I think the best advice is as you mentioned earlier to steer clear of flagstone/sandstone around pools. But it does look nice so there will always be compromise. If I had to do over again I would go with more tile and travertine.

 

[joepaiii]

There is no argument that water erodes stone. That is how the Grand Canyon was created. There is no salt in the water that created the Grand Canyon.

Water created the erosion - yes.

Salt creating the erosion - incidental.

Agree but I still think salt water will cause the degradation faster and it’s magnified with the soft stone used in Texas pools.

 

[RoyR]

Depends on the kind of rock…and if the water is balanced. My waterfall guy picked the wrong rock, I get about a table spoon of rock sand every week…it should last till well after I’m dead, so I am ok with it.

 

[newdude]

So the entire argument revolves around salt being so bad for stone. But all pools have salt. A liquid chlorine pool will end up with at least 5% of seawater and a ‘salt pool’ will be 10% the salinity of seawater. So the argument is really that 5% or *less* difference between the 2 causes all the damage.

Whether the subject is rock deteriorating, or ladders / light niches / etc rusting prematurely, If they are poor quality materials, they will weather from the elements themselves, not if ones pool is ‘salt’ or not.

 

[joepaiii]

So the entire argument revolves around salt being so bad for stone. But all pools have salt. A liquid chlorine pool will end up with at least 5% of seawater and a ‘salt pool’ will be 10% the salinity of seawater. So the argument is really that 5% or *less* difference between the 2 causes all the damage.

Whether the subject is rock deteriorating, or ladders / light niches / etc rusting prematurely, If they are poor quality materials, they will weather from the elements themselves, not if ones pool is ‘salt’ or not.

I am going to try to test the argument of salt levels in non salt pools. I have read it many times here and understand the reasoning behind it. I do wonder though in reality what the levels truly are with rain caused overflow and splash-out. I do know that when I converted my 2nd pool to salt the flagstone became sandy where it had never done that before in the previous 5 years I owned the pool.

Again my point is that if you are going to put stone around a salt pool be careful as I believe that the increased salinity levels of the water will increase the speed of the stone deterioration. Also sealer is beneficial in some locations. Best recommendation is to not have soft stone around a pool period but that is difficult in Texas as all the local stone in this area is poor.

 

[newdude]

Best recommendation is to not have soft stone around a pool period but that is difficult in Texas as all the local stone in this area is poor.

Exactly. What’s locally available is weaker material. To truck heavy stone from better locations would cost almost as much as the materials. Which most folks wouldn’t go for. So the salt becomes an easy target and several years later when the stone deteriorates, the PB is long gone and it’s not his fault.

I do wonder though in reality what the levels truly are with rain caused overflow and splash-out.

Every pool is different of course, but the first thing we recommend before adding a SWG is to test the salt content. Many users are surprised to learn they are well over 1k ppm already. We saw a few 2ks and a 3k this year alone. One member was at 600 ppm from startup alone after a refinish. @Oly was at 4K when he switched and had to drain to meet the SWG levels. And even THAT was still a far cry from the ocean at 30k+.

Rain of course help keep the salinity down more in the southeast with them getting up to 54 inches a year, and less in the southwest with next to none. But even in wet areas, most of what they drain immediately after a storm (or during) is the top layer of rain water that hasn’t mixed well yet, especially with an overflow drain. It falls in the pool and most goes right out the overflow. Some of it mixes of course, but it’s not an exact measure of 600 gallons of rain emptied immediately through the skimmers equals 600 gallons of dilution. So their salinity will eventually climb like everyone else’s.

 

[ccbill]

I am going to try to test the argument of salt levels in non salt pools. ....

My LC pool has 1875 ppm salt. I haven't done any partial drain/ refills for quite some time due to ongoing rainfall issues here in the west. I saw some LC to salt calcs somewhere here at TFP and they lined up pretty good with my 1875 ppm.

 

[joepaiii]

Exactly. What’s locally available is weaker material. To truck heavy stone from better locations would cost almost as much as the materials. Which most folks wouldn’t go for. So the salt becomes an easy target and several years later when the stone deteriorates, the PB is long gone and it’s not his fault.

Every pool is different of course, but the first thing we recommend before adding a SWG is to test the salt content. Many users are surprised to learn they are well over 1k ppm already. We saw a few 2ks and a 3k this year alone. One member was at 600 ppm from startup alone after a refinish. @Oly was at 4K when he switched and had to drain to meet the SWG levels. And even THAT was still a far cry from the ocean at 30k+.

Rain of course help keep the salinity down more in the southeast with them getting up to 54 inches a year, and less in the southwest with next to none. But even in wet areas, most of what they drain immediately after a storm (or during) is the top layer of rain water that hasn’t mixed well yet, especially with an overflow drain. It falls in the pool and most goes right out the overflow. Some of it mixes of course, but it’s not an exact measure of 600 gallons of rain emptied immediately through the skimmers equals 600 gallons of dilution. So their salinity will eventually climb like everyone e

My LC pool has 1875 ppm salt. I haven't done any partial drain/ refills for quite some time due to ongoing rainfall issues here in the west. I saw some LC to salt calcs somewhere here at TFP and they lined up pretty good with my 1875 ppm.

We know that Liquid Chlorine (LC) will raise the salt level over time but the vast majority of pool owners don't use liquid chlorine in the US and definitely not in Texas. Many may have converted over this past year due to supply constraints but I would still think greater than 90% of pool owners use tabs.

In general what would the salt level be in a pool that was not liquid chlorine sanitized - one that used tabs? But that isn't really the point of this thread. The question is about waterfalls degrading due to salt water. Many here say its nonsense. I don't agree but don't have the time or energy to study it more closely. I am going to seal the rock that is very sandy around my waterfall and enjoy the character the erosion causes.

 

[newdude]

and enjoy the character the erosion causes.

My flagstone blocks eroded some (away from the pool where rain puddles sat). It gave them 1/4 inch or so of fingerprint like swirls, peaks and valleys. I thought the character added was stunning. And with 2.75 inches to go, replacing them would not have ever been my concern.

 

[mknauss]

In general what would the salt level be in a pool that was not liquid chlorine sanitized - one that used tabs?

One 8 oz trichlor tablet in a 10000 gallon pool adds 4.5 ppm salt.

That is about half the amount of salt added if 10% liquid chlorine is used to add the same amount of FC.

 

[joepaiii]

Here are some pics from over 2 years later... any recommendations for what I should replace these rock with? I am thinking about some rock look porcelain tiles but I am sure that might be a challenge. I have no idea if this is from the salt levels, just plain erosion or just really bad rocks. I was at a party today and they had a 10 year old non-salt pool with flagstone that looks brand new and it's the same type of rock- oklahoma flagstone

So likely combination of really poor rock and maybe more splash/erosion and hopefully not related to the rock. Interestingly the waterfall segment is fine... only places I am seeing this issue is where there is overspray splashing of water. Which fits the bill of the salt degradation thesis, salt water gets splash into porous stone and then re-crystalizes and cause microfractures to break rock down more quickly.

Anyway - felt like updating this thread. If anyone has any ideas how to preserve these rocks as long as I can let me know. Also if anyone has ideas for how to DIY replacements let me know. Have a great weekend!