Proper finish to use over sanding sealer on floors?

Question:A contractor sanded a (covered) new wood porch for me, then put on a very thinned layer of moisture cured urethane, which I am assuming acts as a sanding sealer in this case. This was not what I asked him to do, but it is done. There is no sheen on the wood and the grain is still fairly rough/raised. Now I am unhappily left holding the ball. The porch gets some morning sun and can get blown rain (through screens).

I will probably sand the porch and then finish. Can I use an oil-based polyurethane? Can I use a water-based acrylic product (my preference)? Any other suggestions? Thanks in advance! -susan (aka sukeylukey)

Answers:
use the HELMSMAN EXTERIOR , it will last for years!