If I can put my 2 cents in. I'm a General Contractor and have done extensive work doing bathroom and kitchen renovations. To properly protect and minimize damage from saltwater is a challenge to say the least. Even with everything done right, you will still need to upkeep and maintain, meaning repainting every so often, to checking any structural supports in close contact to water (should have access panels to facilitate easy access and view). Now as suggested using green boards or better yet cement boards, installing a vapor barrier below the actual panels helps tremendously. Some sort of plastic sheeting, below some aqua bar or other type of specialized water resistant paper/felt underlayment. After the water resistant/proof panels are installed, properly mudding the joints with mortar or using something like drylok extreme waterproofer. Going further, painting with a water proof paint like Marine paint will further give protection. Any metal needs to be properly prepped and painted for use with saltwater. After a year, things should be repainted, especially areas that show any signs of damage creeping around. This may seem like a lot, but if you consider the amount of money spent to make your tank the beautiful display it is. This cost and labor is really just a fraction, and helps insure the beauty and health you've invested in.
Melo1
Melo1