Fiberglass pools are almost 20 times stronger than concrete pools and are manufactured in one large shell. Their strength and composite materials mean they are resistant to temperature changes such as extreme heat and freezing. The smooth, nonporous surface of the fiberglass has a strong gel coat finish, which makes it less susceptible to changes in water chemistry and means algae have a tougher time growing on it. Despite all fiberglass has going for it, it is not totally maintenance-free. Knowing how to care for a fiberglass pool will extend its life for many years.