Cahodic Protection for Stainless Steels in pool water

[rjohnston]

I have an application where I will be putting a large carbon steel structure in a pool water type environment. The chlorine level will be 2.0 to 2.5 ppm. No ozone or bromine. Water temperature to be 84F

The carbon steel structure will be protected using a magnesium ribbon anode on the pool floor below the structure.

The carbon steel structure will also be epoxy painted.

In the system, I also have many SST components (hydraulic cylinders, pins, roller tracks, etc.) Many of the SST components are larger than 4" in any direction. The SST components will be isolated from the carbon steel using non-metallic bushing and the layer of epoxy paint.

1. Is there any need to provide a cathodic protection system for the SST components?

2. Do the SST components need to be bonded to the carbon steel structure? (ie with bonding cables)

Thanks for your help!

 

[Metalguy]

Do not connect the SS to the CS. If the Mg anodes are close enough to the CS, they will protect the areas where the coating doesn't-at least until they dissolve.

If you are using 304 SS, you'll need to keep the chlorides low-316 does a little better. You can have 2 PPM Cl as a biocide with both low and high levels of chlorides.

Keep the pH down to around 7.2-7.6 if you want the Cl to be in the form of hypochlorous acid, which is the *effective* biocide.