If that post is structural, replace it. The salt water of your pool did not cause that. The salinity of the average "salt water' pool is less than that of human tears.
Unfortunatley it is one of 3 structual post. I'll clean it up first and see what state it is under the surface. Thanks, and good point about the salinity.
Welcome to TFP! For a wealth of pool care information please check out our free Pool School. If you are in need of specific help then we encourage you to Register and ask us here in the forum!