Remove your pool's bottom drain cover for cleaning and repairs. Professional pool service companies can do this for you, but if you don't mind getting wet; you can do it yourself. A pool drain cover should be replaced if worn or broken. Anti-vortex, Virginia Graeme-Baker (VGB) Act-approved drain covers must be used to protect swimmers from being pulled by suction to the drain. A number of pool drain covers are manufactured and sold to the public, but only two fastening methods exist. Some drains are twisted down and others are screwed.
Turn the pool filtration pump off.
Put on a face mask or pair of swimming goggles. Pull on a pair of swimming fins. Grab a Phillips or flat-head screwdriver. You'll discover which kind you'll need, if any, when you reach the drain.
Swim down to the drain cover and inspect it for fasteners. If the screws are visible, then screws hold it down. If you don't see any screws, then the cover twists on and off.
Undo the screws, if it's screw-fastened. Twist the cover counterclockwise if no screws hold it down. You may have to swim up for air and then swim back down several times until you get it removed. Lift the cover up out of the drain hole when it has been unfastened.