Im not sure of the brand anymore, but my TBI Suburban tank had quite a bit of rust on it, both inside and out. So obviously I painted the outside, and found a product that lined the inside. You had to clean it out just like your currently doing. Then cover the sending unit hole, pour the product in, cover the remaining holes, and flip flop it all over until your satisfied. Then pour out the excess, let dry, put back together and install. Did it 7 or 8 years ago, and its held up perfectly. Actually when I did the shackle flip this past summer I had to drop the tank, and out of curiosity I pulled the sending unit and inspected the paint like substance on the inside of the tank, and it looked just like it did when I poured it in originally. Didnt flake or clog the pump sock at all.