I'm replacing the exchanger damaged by a salt water pool. Heater leaked for 1-2 months and of course, was worse towards the end. I have removed the exchanger and am cleaning the interior around the box. Everything looks fairly straightforward as far as replacement. One issue is that the fire tile is wet. It looks undamaged, with some discoloration from the water. There is some soot lying on the bottom and minor scorching on the side opposite the header. Scorching and discoloration is less than 1/16th of the entire surface. While I'm thinking that having wet tile might be beneficial, I don't know the properties of the tile and water might be damaging.

Any help would be greatly appreciated along with any suggestions,(aside from gas/power turn off and wire labeling), of things to look out for.