Salt Water Damage To Pool

by Diane
(Toronto, Canada)

I have a 15x30 aluminium pool. Part of the pool has a deck around it. At the beginning of this pool season I noticed holes in the pool wall at the bottom, underneath the deck. I have a salt water system.

Could it be that the salt has damaged the wall or did I just get a "dodgy" pool wall. Has anyone experienced this?

Thanks for the question Diane

Yes, it could be possible that this is salt damage. Some of the plumbing at the YMCA pool where I was the pool operator was similar to this. It had a crusty layer of salt that could be chipped away. You may have a pin-hole in the vinyl that is causing water to slowly leak and build up a layer of crusty salt.

If you have a high calcium hardness level and are unable to lower it through water dilution, then you can lower the total alkalinity and pH in order to prevent and/or slow scaling. With salt pools the alkalinity can be down to 60 - 70 ppm and the pH can be lowered using muriatic acid to 7.2 - 7.4. In some extreme cases, you can use a metal sequestrant designed to reduce calcium levels and inhibit scaling.

Was is the salinity of the water? Is it in range, or too high? Many chlorine generators have a range of 2500 - 4200 ppm.

It also could be calcium build-up. What is the hardness reading? Do you have hard fill water, above 250 - 300 ppm? Do you use calcium chloride if you have soft water? Do you use granular chlorine (calcium hypochlorite) to shock the pool? All of these will increase the hardness of the water and can cause calcium build-up.

There are two benefits of having a salt water pool. One is the salt makes the water feels better. It's a little softer than a regular chlorine pool. 2nd is you don't need to add chlorine on a weekly basis. The salt chlorine generator takes care of this.

Hope this helps and have a great Summer.


Comments for Salt Water Damage To Pool

Click here to add your own comments

Jan 05, 2015
Unknown Salt Water Pool Stains On White Gunite Walls
by: Anonymous

We installed the pool in 2005 in Anaheim, California. It has been a nightmare finding a knowledgeable pool service for routine pool maintenance and weekly cleaning.

All the pool services will tell you they work all the time with salt water pool maintenance and usually within the first month the pool is green and chemicals out of whack. I let all of them go and finally took over the task.

I was doing well until last year and had a green algae bloom on the south wall of the pool. I shocked the pool and brushed off the green algae and all seemed well with only a little algae show when the chemicals would get off.

This year the chemicals were off and a new type of staining was seen. It does not brush off. It did not clear up when the pool was shocked. The color is bright light blue with some black stains seen on the north, south and west walls. The bottom is not affected. The pool water is a beautiful blue. The chemicals are all within limits.

Can you tell me what the pool has and how to cure it?

The filtration system is Polaris and we run the filter 4 hours/day and have a pool sweep. The pool sides are white gunite. The pool size is 36,000 gal.

Thanks for the question

First, I'd like to have your complete chemical readings:

Chlorine, CYA (cyanuric acid/stabilizer), pH, Alkalinity, Calcium Hardness, and Metals (iron and copper) and names of any algaecides you may have used along with clarifiers, phosphate removers, and/or flocs. I'd also like to have the salinity range you've kept your pool.

It makes troubleshooting much easier and the process of clearing up your pool will go much faster. You can get this done at your local pool store.

There could be many reasons why a pool's surface stains and the readings can narrow it down a bit. Also, what is the salinity range for your particular chlorine generator? Most are between 2500 - 4500.

You also need to determine what kind of stain it is, either organic or metal. This is done using a Trichlor tab. Put it on the stain for about 5 minutes. If the stain lessens, it's algae and you'll need to shock. If the stain doesn't lift or gets darker, it might be a metal stain. Get some crushed up ascorbic acid (Vitamin C) and put about 1/2 lb. in a sock and place that on the stain. If it decreases you'll need to do an ascorbic acid treatment.

The possible algae is caused by the chemicals being off. Salt pools are different than regular chlorine pools because the chlorine generators need to be dialed in according to the pool use, heat, sun, etc...

Without the numbers I'm just guessing at what the problem is. Get back to me with the chemical numbers and I'm sure I can help.

Click here to add your own comments

Return to Above Ground Swimming Pools.