Anyone Had Corrosion Issues With Salt?

[bonnieboop]

Hi,
Forgive me for not having the usual "description," under my name, but I'm new here -- and i'm in the "research," process of building a pool. I've met with 6 pool builders (2 more highly recommended ones to go), and am just now trying to parse out what I want (and need). One pool builder (highly respected in the area in which I live -- MetroWest Boston suburbs), said that his company no longer recommends salt systems and are reluctant to install them. He cited equipment failure down the road due to corrosion from the salt. He was the only pool builder my husband met (as he came out on a Saturday -- all the others have come out during the week, when my husband has been at work), and once my husband heard about the "corrosion," issues with salt systems, he's said "Nyet," to salt ever since.

I've heard from all the other pool builders I've met that people love their salt systems, there is not widespread equipment failure down the road due to corrosion from the salt, and unless one is putting in a metal ladder (for example), rust or corrosion isn't a problem.

What is the consensus here? The pool builder who is recommending against salt recommends a "chlorine erosion feeder with Clear 03 Ozone and Ultra UV Purification System," and claims it feels just as good on the skin as the salt system.

Opinions? Comments? Help!

Thanks so much in advance.

Best,
Bonnie
(looking to build the best pool she can)

 

[JoyfulNoise]

I'm mobile right now so I can't properly comment but I can make a few points -

1. Chlorine puck erosion feeders are a bad idea. They lead to over-stabilization (excess CYA) in the pool water.

2. UV/Ozone systems are expensive toys that are not adequate for pools. You can search the many posts on TFP about just how useless they are.

3. Salt pools operate at ~3400ppm salt. That's about 10X lower salinity than ocean water. Metal corrosion is caused mostly from builders using sub-standard or incompatible materials like low grade stainless steels or Aluminum tracks for liners. Corrosion of metal is dominated by pH, especially low pH. So if your pool water is properly balanced, you have no worries about corrosion. In fact, those pucks that are used in puck feeders, they are very acidic and excess trichlor use typically leads to crashing TA and pH. And that is what does the most damage.

Get quotes and build proposals with specific equipment details and we'll be happy to help you parse them and cut through the BS.

Good luck,
Matt


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[pooldv]

+1 to all of that. This is my second saltwater pool. We are over 3 years in and everything is great. If I ever build another pool it will definitely be saltwater.

 

[azjoshers79]

I recently met with 4 major builders in the Phoenix area. They all said the same thing, "no salt and get an ozone system". I started doing research and from what i have found is ozone is not very effective in outdoor pools. Every builder tried to steer me away from salt. I have since decided to do an owner build with the assistance of a general contractor and he is favorable to salt pools. He has built over 100 pools and actually has a salt pool himself. He loves it. I am going with salt. I think the builders are on this ozone kick because the units are actually cheap for the builder and they can markup very high for a good profit margin.


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[Griswald]

Horrible corrosion...after 3 years, my metal pool ladder has about a pin head spot of rust!!!!

Oh NO...what to do.

Seriously, any pool builder worth a carp will give you powder coated parts. They do not corrode any worse than any other metal in water.

One thing that the salt water does do is eat the bristles off of pool vacuums and wall brushes and eats the cheap polypro rope that comes with the shallow to deep floats.

And, for some reason, animals love the taste of the salt water. 2 of our cats drink it, one stray that keeps showing up drinks it, when the neighbors bring their dogs they drink it, we always find evidence of other night-time critters hanging around and frogs seem to think we own a swamp. It must not be too bad if nature loves it!

 

[yostmatt]

I have a SWG on an aluminum pool. My pool is a little different and does not have a track. In one year of usage, no issues. I contacted the manufacture and they said salt will not void the warranty. He also said, they found liners lasting longer with salt systems.

Of course the pool store would tell you not to buy one. They want you in their store once a month, spending hundreds of dollars each trip, and not just once up front. I only have to add MA about once every 10ish days, to deal with a slow PH rise.

 

[JoyfulNoise]

I have a SWG on an aluminum pool. My pool is a little different and does not have a track. In one year of usage, no issues. I contacted the manufacture and they said salt will not void the warranty. He also said, they found liners lasting longer with salt systems.

Of course the pool store would tell you not to buy one. They want you in their store once a month, spending hundreds of dollars each trip, and not just once up front. I only have to add MA about once every 10ish days, to deal with a slow PH rise.

One way to avoid corrosion of aluminum is to use a magnesium sacrificial anode (as opposed to using zinc for iron alloys). Perhaps your Al pool has a sacrificial anode in place?


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[Pilotwerx]

I can tell you with great confidence, ozone and uv is a waste of money in a pool. The only place I have seen it beneficial (I am pharmaceutical engineer) is as the last defence of water that has been chlorinated, carbon filtered, cartridge filtered and processed through an RO machine. Ozone is a powerful and dangerous oxidizer but the amount of gas that would be needed to disinfect pool water is unreasonable.

 

[azjoshers79]

I can tell you with great confidence, ozone and uv is a waste of money in a pool. The only place I have seen it beneficial (I am pharmaceutical engineer) is as the last defence of water that has been chlorinated, carbon filtered, cartridge filtered and processed through an RO machine. Ozone is a powerful and dangerous oxidizer but the amount of gas that would be needed to disinfect pool water is unreasonable.

I was originally considering ozone because every pool builder is pushing it hard here in Phoenix. Telling me salt is a mistake and that with ozone I will use 1/4 the chlorine. I have decided to ditch the big builder and build it myself and go with salt. The builders here talk about it like its the most amazing thing since sliced bread



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[TruckLoan]

I am getting ready to renovate my existing pool including a switch from chlorine tabs to an automated system and I have also had 4 of 6 builders in MA try to steer me away from a SWG toward an Ozone/ UV combo system. It is also corrosion from salt that they are all using as the reasoning for that switch but not corrosion in or around the pool. Primarily they point to the heat pump and claim that even with a sacrificial anode, the life of that one unit will be about half or less. I just put in a new 150k btu heat pump last year for nearly $5k and I have heard 7-10 years is the normal life expectancy, which seems short already but needing to replace it in half that time would make me very unhappy.

I have yet to find anything positive about ozone for a residential pool other than manufacturers press and occasional owners defending their systems on the forums but I am somewhat stumped as to why so many builders seem to be proposing these systems. It can't be profit, even if the margins are a little higher than a SWG, the ones I've been quoted on so far all come in about 20-25% lower than the SWG options, so I can't see how they can make enough more money to make it worth pushing a less efficient system. Has an ozone mfg rep in this area learned how to brainwash pool builders?

 

[JoyfulNoise]

I am getting ready to renovate my existing pool including a switch from chlorine tabs to an automated system and I have also had 4 of 6 builders in MA try to steer me away from a SWG toward an Ozone/ UV combo system. It is also corrosion from salt that they are all using as the reasoning for that switch but not corrosion in or around the pool. Primarily they point to the heat pump and claim that even with a sacrificial anode, the life of that one unit will be about half or less. I just put in a new 150k btu heat pump last year for nearly $5k and I have heard 7-10 years is the normal life expectancy, which seems short already but needing to replace it in half that time would make me very unhappy.

I have yet to find anything positive about ozone for a residential pool other than manufacturers press and occasional owners defending their systems on the forums but I am somewhat stumped as to why so many builders seem to be proposing these systems. It can't be profit, even if the margins are a little higher than a SWG, the ones I've been quoted on so far all come in about 20-25% lower than the SWG options, so I can't see how they can make enough more money to make it worth pushing a less efficient system. Has an ozone mfg rep in this area learned how to brainwash pool builders?

Unfortunately you just have to assume most of what the PB's say in terms of chemistry & equipment to be BS. I don't know why there seems to be this big push towards UV & Ozone systems but perhaps they're cheap to install and they get higher kickbacks from the manufacturers at the end of the year if they sell enough units. The chemical facts are indisputable though - UV and Ozone systems are completely undersized for residential pools and are only considered as a secondary sanitation source by the EPA, i.e., you MUST still use chlorine.

As for corrosion, once again, the salt levels found in pools is not the controlling factor. Metal corrosion is almost entirely dominated by pH and, to a lesser extent, dissolved oxygen levels. Once the pH gets low enough (below 7.0), the passive oxide coatings that form on metal surfaces breaks down and corrosion can happen. Salt, if it plays any role, only tends to accelerate certain types of corrosion in some kinds of metal, e.g., crevice corrosion in ferrous metals. I would have advised that your heater have a titanium or cupronickel heater exchanger but even regular copper is fine. If you keep your pool water properly balanced and don't let the pH get to low, then the heat exchanger will be fine. As well, if your pool and equipment are properly bonded and grounded, then using a sacrificial anode is just secondary insurance.

The funny part is, the PB's want you to use Ozone and a trichlor puck feeder. Well, trichlor pucks are very acidic (pH can be as low as 4.5) and residual ozone can be a powerful oxidizer although ozone does not stay resident in the water for very long (it has a short half life). So the system the PB's want to instal are far more dangerous from a metal corrosion standpoint than an SWG.

 

[TruckLoan]

I would have advised that your heater have a titanium or cupronickel heater exchanger but even regular copper is fine. If you keep your pool water properly balanced and don't let the pH get to low, then the heat exchanger will be fine. As well, if your pool and equipment are properly bonded and grounded, then using a sacrificial anode is just secondary insurance.

I actually thought of checking with Aqua Comfort (the heat pump mfg) this morning and was assured that all their heat exchangers are all titanium and I should have no concern at all about salt and the sales/support guy I spoke with even said a sacrificial anode was not needed but inexpensive enough that it still was a good idea to ensure everything else in the system was more fully protected. He claimed he has a salt pool personally with a similar heat pump to mine (previous generation) that he has had for eight years with no issues so far. And their HQ is about 100 miles from me so similar environmental factors. I think I have enough to commit to salt.

As far as profitability on one system install vs the other, I use the unscientific method of looking at web prices for the equipment alone and comparing the differences. Using that method, there cannot be much difference if any in profitability one system vs the other.

 

[JoyfulNoise]

Glad to hear it's titanium !! There's no way Ti can corrode from salt, at least not at any normal pool water pH. If you can easily do a sacrificial anode, I would but not if it's going to be a PITA.

As far as profit margin goes, PBs can typically get equipment at a stiff discount directly from the manufacturers and even more so if they bundle their systems. Add to that the annual rebates they can get for making high volume sales, then there might be a higher profit margin on UV/Ozone versus SWGs. Impossible to know from the customer side of the process.


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[chem geek]

They are using the ozone as a crutch to try and kill algae that is free-floating given that the CYA will rise with continued use of Trichlor. That won't help with algae growing on surfaces or that otherwise doesn't get circulated unless enough ozone is produced to leave some residual and that is unlikely since they are usually undersized and designed not to produce enough to risk outgassing from the pool.

 

[duraleigh]

All posts related to storage of MA have been removed from public view. It was a clear thread hi-jack.

One of the most difficult things keeping this forum logical is that all posters need to keep their posts concise and on the subject.

A thread hi-jack would seem to be no big deal but it often is a huge issue and completely derails the idea of OP's post.

 

[ConradM]

Salt water is the way to go. 3400ppm is just enough salt to make the system work. The ocean has 36,000ppm. A tear has about 6000ppm. The corrosion comes from what the people have posted.