Pool accidentally draining! how do I shut off the main drain??

[futility]

suddenly it's draining!

Got clear enough to see bottom and enjoy.

Main drain cover was broken, bunch of bricks/rocks in there. I pried one out with a pole and a few hours later I've lost 6" of water. could the rocks have been holding a plug in? I don;t know how to stop it. Pool is from 19878. drain looks like a skimmer basket, can;t make out what is down there. are they designed to be operated from above with a pole? so I have to swim down to turn it off? can I put a rubber welcome mat over it to stop the flow until I figure it out? would be a shame to lose all the water I just spent a month cleaning!!!

 

[JohnT]

The drain is normally connected to the pool plumbing. Usually the plumbing connects from the side and there is a hydrostatic relief valve in the bottom for gunite pools.

 

[JamesW]

Most likely the hydrostatic relief valve is stuck open.

 

[futility]

Most likely the hydrostatic relief valve is stuck open.

Thanks! I think that's what it was. A couple of trips down with goggles revealed a large threaded plug. A couple of more 'dives' and I had it screwed back in and haven;t lost any more water. Adding enough to reach the skimmers so I can run the pump again!

 

[Tristan]

This happened to me before, cleaned the filter and didnt put top on perfectly right(it can be a pain). Went outside 30 minutes later and i see half my pool water gone