spoon":2inv11cb said:There is also a product I have used that you pour into the tank and coat the inside with that works very well if the tank has a lot of tiny holes to seal. It requires removing the tank and cleaning out any loose rust etc from inside but it works really well. I can't remember the name of the product but I believe I have a partial can of it somewhere and can get the name if you'd be interested.
More info added.
Go here to find the product I mentioned. I've used several of their products and they are very good.