Fiberglass Pond and Gel Topcoat

I picked up a free 9x4x3 850 gallon fiberglass pond. It's sturdy, and the current topcoat is structurally fine, no cracks or chips, but isn't very pretty.

I want to put a new blue color gel coat on the top. Apparently the product I need is a gel topcoat. Does anyone know what brand or specific product I can use? It's for an outdoor reef.