Main Drains

Now that the pool shell is clean, inspect the main drains and remove any remaining debris. The main drains have something called a Hydrostatic Valve. This valve is meant to keep ground water from coming up into the pool. The rubber o-ring on the Hydrostatic Valve can go bad, so replace if needed. If there are any plugs in the drains (which there shouldn't be), remove them. Replace the main drain covers and secure them with screws