Above-ground pools getting rust is a big issue. During my now 38 years of working with abovegrounds in Orlando, I have seen all kinds of rust for all kinds of reasons.
I have also seen a lot of rust on above-ground pools that can’t be explained. It seems that 29 years ago, I had no problem putting the “why” on rust. With approaching four decades of observing pools, I’m now more uncertain of the origin of rust.
Deductive reasoning and common sense usually serves me and others well in determining things. When it comes to things like leaks and rust with above-ground pools though, what clearly looks like the culprit oftentimes isn’t.
FIRST OFF, SALT WATER ABOVE GROUND POOLS CAN NOT CAUSE RUST IN THE WALLS
People love to blame having a salt chlorine generator on their above-ground pool for the rust it developed. I did too early on with salt pools. Until I saw the same rust in the same places on the same models of the same manufacturers whether the pool was a salt pool or not.
What’s accurate here is that if someone gets rust on their pool and it has a chlorine generator (salt pool), then they will blame the salt water.
And if someone gets rust on their pool and it doesn’t have a chlorine generator, then they blame something else. That’s the reality.
IF YOU USE CHLORINE FOR YOUR POOL, THEN IT ALSO HAS SALTWATER
I’m not going to get into the chemistry here. I’ll just say that all pools that use chlorine have salt in the water. The difference can be the amount of salt. Some older pools that have a residual of salt from some years of shocking/tablets can have a higher content of salt than what is required for a salt chlorine generator (salt pool) to work.
Certainly, salt water can be extremely corrosive. Anyone living close to Cocoa beach knows this. Salt water above-ground pools though only have about one-tenth of the salt as the average ocean. This isn’t enough to cause much damage if any from wind blown or splashing exposure.
UNLESS FROM A LEAK (OR A BEAD CHANNEL) SALTWATER NEVER TOUCHES THE POOLS WALL
There is a liner between the water of a metal-walled above-ground pool and its wall, so to think that salt water somehow causes a wall to rust out is most likely inaccurate.
8 REASONS AN ABOVE-GROUND POOL WILL GET RUST
1 A leak (Number one reason)
Having a leak somewhere in the liner against the pool’s wall is by far the number one reason a pool will develop rust. This is why is super important to fix the leak ASAP.
Most leaks are at the only two openings in the liner, which are the skimmer and return fitting. Seeing rust under the skimmer box or return line is a sure sign that the skimmer or return has been leaking for a while.
2 Ground moisture. But only sometimes
I have seen rust at the bottom of above-ground pools often. Sometimes I can tell why and sometimes I cannot.
Sometimes the earth is wet regularly around and under the pool. With this, the moisture may eventually get under the protective coating on the pool wall and it starts rusting.
Sometimes the bottom track will rust out but the wall is perfect. Sometimes the wall rusts out and the bottom track is perfect. With this, it’s hard to tell why one metal part of the pool got rust while the other got none.
NOTE: I have seen the bottom of pools rust out when they were high and dry. With that, I have no explanation.
In Orlando and Central Florida, we get morning dew where everything get wet. But then when the sun comes up, everything dries out. As long as everything is getting dry, you should be good.
3 A hole in the wall
Above-ground pools get holes from lawnmowers, kids throwing sharp things, and other ways that go unclaimed. Sometimes people shoot pools. I mean, this is Florida.
Having a hole in the wall means that rust can begin. And when rust starts, it continues. Fixing a hole in the wall to prevent moisture from getting in quickly is a good idea.
4 Manufacturer defect
I don’t make metal walls and other parts for above-ground pools, so I can’t say why they fail and start to rust, but I can say that they do.
Pools will randomly just get a rust hole in the wall for no reason. Then there will be another. And there will be no sign of a leak. They just start rusting.
The same goes for other metal parts of the pool’s frame. They will rust for no reason and usually within the first year or so.
5 Trapped moisture due to poor design
Above-ground pool frames have top connector plates and stabilizer bars which are under the top rails and top caps.
If a particular model isn’t designed OR engineered well, then rainwater or pool-splashing water can get trapped under the top rail and just sit there until it starts rusting out the metal parts.
In Orlando, we get a lot of rain often. If your pool has a poor design, it will trap water all summer
6 Bead channels
If your pool has a beaded liner, then the top of the liner feeds into a channel near the top of the pool’s wall.
This channel comes in pieces of four or five-foot sections that butt together. Where they butt together, water can get into the crack and go drip in the back of the liner between it and the inside of the wall. Not good!
I never recommend beaded liners for above-ground pools for this reason. They will cause a pool wall to rust at every section of the bead channel.
7 Trapped chlorine gas
As corrosive as chlorine is because of its salt content in the water, chlorine as a gas is twice as corrosive. Now, chlorinated water will gas off some at the pool’s surface.
If the pool’s top frame design allows for air to get trapped under the top rails, then this very mild but very corrosive chlorine gas will get trapped and cause rust under the top rails.
This is why your metal top rails may have more rust underneath them than on top.
PREVENTING RUST IN YOUR ABOVE-GROUND POOL
I truly wish I could give you a detailed list of things to do to prevent your pool from rusting. The reality is that I can only recommend one thing.
When your pool gets a leak, find it and fix it as soon as you can. That is all I’ve got.