Things You'll Need
Return line plugs
Fiberglass pools were first made with a smooth plain white finish and resembled bath tubs which made them much less popular than concrete or other types of pools. Today fiberglass pools come in many different shapes and sizes; they also come in a variety of different colors and are just as popular, if not more popular than than any other pool. When winterizing your fiberglass pool, or any pool for that matter, if it isn't done correctly you could encounter costly damages when the pool is reopened.
Vacuum the entire pool thoroughly removing any algae or dirt and shock the pool with chlorine the day before you will close the pool. The recommended chlorine level should be around 10 ppm.
Remove all the eyeballs on the returns, which are the small round plastic fittings, using a flat head screwdriver.
Drain the water until the water level is at the bottom of the skimmer by disconnecting the main water line that connects to the pump.
Drain the water from the pool pump and the filter tank by removing all the drain plugs located at the bottom of the pump and the tank. Remove the filter and store in a dry area.
Plug in an air compressor and connect and air hose to it. Insert the air hose into the disconnected water pipe at the pump and blow out the remaining water in the return lines back into the pool. On the return lines in the pool where you removed the eyeballs from, insert the plastic plugs that thread into the holes. Tighten them down with a flat head screwdriver. Remove the air hose from the pipe.
Place a gizmo into the bottom of the skimmer by threading into the hole at the bottom of the skimmer. This allows you to remove all the water from the drain and skimmer lines.
Place the air hose into the drain and skimmer lines and blow all the remaining water out. When the water stops shooting out of the top of the gizmo the lines are completely drained. Remove the air hose and place the plug on the top of the gizmo.
Cover the pool and shut of any electric running to the pool at the breaker.
Make sure all water is out of the lines to avoid damage over the winter.