Vinyl pools are a popular choice because they are affordable. They consist of a vinyl sheet liner that fits tight around the pool’s surface, typically sealing around the deck. Vinyl is more flexible than concrete and more cost-effective than fiberglass.
I wouldn’t apply fiberglass coatings to my body as I don’t like to inhale it. Methyl Ethyl Ketone or MEK is the catalyst for isophthalic resins - there's no Bueno! An epoxy will work fine. When applying coatings in an unventilated area, be careful of gaseous fumes.
Check for cracks in the structure before you begin priming. Any cracks or holes can be filled with underwater pool patching. The style of your pool will dictate the type of patching that you do. You should call a contractor if there are any significant cracks.