Poseidon room glitch?

[Young Willstopher]

The block that you need to move to raise the water level will not let me return it to the original position to lower the water level again. Any work around for this apparent glitch?

[Ruhenlos]

It's not a glitch, it's just a bit clunky.
You have to make sure that the box is well aligned with the mouth of the fish. Try changing up the angle a bit if it doesnt work on first try.