Help - waste setting on filter drained pool

[Poconos]

You probably had a siphon going. Quite common if the waste discharge from the waste port is lower than the water level. Most likely to occur with AG pools. Don't worry, just switch the valve to FILTER when you're done dumping water.
Al

[handy1]

Thanks! Actually it's an inground pool, but yes the output is lower than the pool level. I'm just waiting for more torrential rain now...