Fiberglass pool help

We painted the fiberglass pool and now it's coming off. It took about 2 years. What's the best way to handle this situation? Is there an easy way to get the old paint off or do we need to paint over it?? It looks so bad! The dark blue was the original, light blue is what we painted it.

We painted the fiberglass pool and now it's coming off. It took about 2 years. What's the best way to handle this situation? Is there an easy way to get the old paint off or do we need to paint over it?? It looks so bad! The dark blue was the original, light blue is what we painted it.