Hi @missbzmail, Welcome to Connect. I haven't made use of a salt water pool and have only been in salt water while swimming in the ocean years ago. I think it's good to listen to your doctor since they know you best. From what I've read, salt absorbed through the skin is different than salt ingested and absorbed through the digestive system. I found this interesting article that sort of explains it but not too clearly for this layman's brain.

"Studies in humans have shown that skin could be a buffer for sodium and that skin sodium could be a marker of hypertension and salt sensitivity. Skin sodium storage could represent an additional system influencing the response to salt load and blood pressure in humans." -- Skin Sodium and Hypertension: a Paradigm Shift? - PubMed: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6153561/

Do you mind sharing how you found Connect?

Why did the nephrologist make this recommendation? I can find no scientific evidence, nor any studies, that indicate salt on the skin can cross any cellular barrier into the body. And I have looked a lot because a swimming pool vendor made the statement and could not support it except by saying "the whole body is connected, so logically..."
The article John cited investigates dietary sodium reaching the skin, but doesn't look at skin sodium being absorbed into the body...
Sue