316 stainless steel 1

I think that with hevily cholrinated/wet environment you have to use either inconel or monel alloys. But that is really just a guess. someone will be along presently who actually can answer your question with real informaiton.

You might want to look at Duplex stainless steel (2205 or 2507 or AL2003) alloys for strength and resistance to chloride pitting attack and CSCC.



Also, you might want to check this thread regarding some newer duplex stainless steel alloys;

thread1135-127951

I found a document from the Nickel Development Institute which addresses this exact issue called "Stainless steel in swimming pool buildings". It can be downloaded from their website.