Rust issues

[ninjarider]

I'm having difficulties getting the rust out of my tank for my sorely needing tlc xj. I read radare's thread about rust removal for tanks and chose to use evapo-rust instead of acid. The issue I think is that a PO coated the inside of the tank with a sealant and therefore my attempt didn't yield the desired results. My question is if I use muratic acid will it cut through the sealant? And secondly if it does work what kind of hazards should I possibly expect (fumes etc.) What kinds of safety materials will I need. Here is a picture of a flake of the sealant.