Under the Swim Step?
If it is like my Vision 32, and under the swim step, you may have to cut it out. That is what I did. I rinsed it real well a few times, and used a grinder to cut the tank in half. It was a 12 gallon tank. I replaced it with two six-gallon tanks I linked together since those were the only ones I could get to fit through the locker openings. Yes, you definitely want to replace it with poly. this is a job you want to do only once. RD