Brown stains on Stainless trim

[Alpha pools and spas]

Hi can anyone help
We have a salt water spa that is only 6 months old, the water chemestry is fine PH 7.5, Low cal, Free clorne is on the low side Alcalinity is good  but we have a brown rust like stain on the stainless jet trim  this can be cleaned of with metal polish with no sign of corrosion on the trim after cleaning
between the trim and plastic jet the staining is worse, there is also some jet black soot like staining on the satinless screws holding the back plate over the massage jet.  we tried a common rust removal chemical and it had no effect.

The spa water looks a blue green colour but it difficult to say if this is real or just the effect from the sun and sky

It looks like some form of electro plating on the stainless trim

Any ideas

[goneaway]

Stainless still rusts, but not as quickly.
Maybe the salt is causing it ?

[Alpha pools and spas]

OK but as i said when you clean the stain there is absolutely no sign of corrosion on the stainless it is as new

[MarKee]

I bet the salt has something to do with it.  It's very rare for stainless jets to rust in a hot tub because they are submerged under water, and rust needs oxygen to form.

[bob snader]

Is the tub properly grounded? Electroplating is the only thing I can think of other than the above noted salt reaction.

[Alpha pools and spas]

Thanks bob  as far as I know its grounded but will check  it looks like electroplating to me as the stainless has not rusted it has a rust colour coating on it but also a black coating in places this looks to me like electrolysis Anode and Cathode

We have tested the water for metal but the test is clear

David

[rin-spa-aic]

Had this problem with salt in our stainless tub. Mostly on some of the welds, but some flat areas of stainless as well.

After a lot of troubleshooting it was determined it was a oxidation reaction of the salt to metals in the water and not to the stainless.
The stainless just happened to be the place the metal oxide stuck to first.

The deposits came right off with a chemical added to the water.

It ended up too much of a pain so we just scrapped the salt system.

[Sam]

This is common with salt systems and just one more reason I am not a fan of them.  It's not difficult to manually add chlorine.  People have it in their minds that hot tub chemical maintenance is difficult and that salt systems will somehow make it easy.  Some salesman seem to be more than happy to perpetuate this and up-sell to a $1500 salt system.  We see significantly more problems with people who have salt-systems.  They're just not worth it.

[Alpha pools and spas]

What chemicals did you use to remove the stain ?   Telling the customer that a salt system is a waste of time and money when they specificaly asked for it is not really an option

[rin-spa-aic]

The chemical recommended and used was call PST (Pool Stain Treat).

http://www.amazon.com/gp/product/B004VU8WJQ/ref=as_li_ss_tl?ie=UTF8&camp=1789&creative=390957&creativeASIN=B004VU8WJQ&linkCode=as2&tag=r1rinaicfavor-20

It worked like magic.
If you get impatient for it to work over time during filtration cycles in the you can rub it directly on the surface.
A couple bad spots I just kind of mounded it up on the problem area and let it dissolve.

We installed the salt system because we were putting on on the pool and figured hey, why not?
The company that manufactured the spa said they do not recommend salt in their tubs and that many people have different issues maintaining a salt system in a hot tub. They did know of some instances where people operated them fine with no issues, but the official recommendation was against.
Decision was made that the salt system was potentially more trouble and maintenance than it was worth for the spa, so we removed it.