For other people who find this thread looking for tank advice here is some info that took me a good while of searching on the net to find. Since you pulled out about a square foot of old liner out of your tank there is a good chance that the rest of the stuff is flaking off and plugging things up.
Go to lowes/homedepot, and in the paint section buy 2 gallons of MEK (about 22$ each) and slosh that stuff around to dissolve the old liner. While your there you might want to get some rust preventer with phosphoric acid. Word of WARNING MEK is Extremely flammable, so be careful with it.
After cleaning up the tank you may want to reline it with a higher quality liner, I have heard good stuff about "Red Cote" you can still pick it up at oreillys for about 20$ a can, you will need 2 cans.
I know alot of the older guys that give advice about cleaning your tank would say to take it to a radiator shop and have them boil it out for you... now that is good advice, But nowhere in my area was there a rad shop that still did that.