Bought a home with an 18000 gallon in-ground concrete pool (built in 1971.) The home has been vacant for a few years and working through the pool problems (as well as other house problems.) Thanks for all the help so far as I have never owned a pool.

PoolForum helped me diagnose the sand filter was not properly functioning and the shop vacuum trick to change the sand was a great tip. Problem was the filter was filled with playground sand by the prior owner; can personally verify that playground sand will NOT filter your pool.

PoolForum also got me the correct test kit (2006) so I could determine I have very high alkinity (250), CH (400) and CYA (200). I think the real estate broker would just come by once a week and dump in pounds of shock; so I need to dilute. Which gets me to my question: the drain and skimmer are not separately valved so unable to drain with the pool pump to waste. Can I use a large rubber stopper in the skimmer intake or should I get a submersible pump?