Stump question

I am building a deck next to an above ground saltwater pool.

I would like to use stirrups, but would the salt water be too corrosive?

Alternately i will put the stumps directly inground. I was going to use Cypress, as it will continue through the deck as the post for the fence. and maybe H4 treated pine on the internals.

Is timber in the ground concreted in or is it rested on concrete soleplates/pads and backfilled?

The diagrams in Allan Staines bock have concrete pads, then gravel and then concrete again


More...