Are you sure the fence is made of iron or steel? Most are either anodized aluminum or galvanized steel. Actual wrought iron would be awfully expensive.
Is it painted?

Scott

My bad Scott! I thought those terms were interchangable. It is powder coated steel and will be 10 to 15 feet away from the pool. My code enforcement guy told me his had rusted so badly that his square rails were becoming round.

Poolcenter, Thank you for the info!

The quality of the powder coat is going to be important but @ 15 feet away, should be fine for many, many years.

Salt, in and of itself, is not corrosive. Add water and it becomes an electrolyte, that is , it can conduct electricity. For example, look at your salt shaker. Ever seen one rust?

The zinc anodes POOLCENTER was referring to are to keep any metal that comes in direct or extremely close contact, such as ladders, light fixtures, rail sockets, etc... keep stray currents from being attracted to them. The zinc attracts the currents and it corrodes the zinc, which doesn't cause the pool any problems with staining, pool chemistry, or pitted stainless.

Scott

Great info, Scott. Thank you!

It is called galvanic corrosion and it is a very real problem. You can potentially create stray voltages on metal components in and even around your swimming pool. Sacrificial annodes are required on any salt water pool in my professional opinion.

The absolute best thing you can do to protect your pool and your fence as well is to ensure that everything is properly bonded. If you have a grounding plate or bonding wire installed onto the fence this will essentially eliminate, or drastically reduce this concern of rusting.

If you want more info on it check out the link that goes more in depth into the chemistry hehind galvanic corrosion and salt water swimming pools.

Here is a link that might be useful: Pool Salt Water

Sacrificial anodes won't do much of anything for a fence that is 15' away even if it is connected to the bonding system. Even then, keeping the base of each post a couple inches above the surrounding soil level and pitching the concrete footing it's set in will be most beneficial as this would keep any runoff away.

Scott