My sump tank is buried in the ground about 5’. The tank is about 425 gallons this is about 3,544.5 pounds of water.
http://ecorenovator.org/forum/44310-post44.html
We have had very hard rain for a couple days and some flooding in my area. I guess the water table is up and lifted the sump tank about 6 inches. Crazy it was able to lift all that much weight. It lifted the tank into the grow bed.
I have a pipe braces the pipe for the gravity feed. It raised that pipe and stopped the flow to the grow bed.
I put in an emergency overflow pipe that just goes back to the sump tank if the gravity feed pipe is closed off. I have now tested that emergency overflow and it works well it kept the fish tank from overflowing.
This tank has never moved at all the last two years.