I used the full POR Kit 2 Summers ago, I had only surface rust in the inside of the gas tank and was going through my complete fuel delivery system. The process called for Step 1, Marine Clean to clean the tank, Step 2, was Metal Ready, and Step 3, was a product called US Sealer. This stuff is nasty as I recall I followed the directions to the letter and it cured up in no less than 72 hours. It all works fine and recently I changed out the gasket between the top of the tank and the expansion tank and was able to look down in the tank through some gas which magnified the inside. Everything was in great order and looked wonderful.....as far as inside of gas tanks are concerned?
I was happy with the system, but it was a 3 part system, if you ever do it make sure you have thick rubber gloves on when dealing with the Sealer, it's silver and I had no intention of touching that crap, next thing you know I thought I was Capt. America with silver hands.
For what it's worth, CSN.
Vysoc