Yikes Wood! Sounds like you might need to rig some gutterguard up over the tops of overflows to keep that little guy in the display from now on.
Cyclopeze flake food is always good to have around. Frozen Mysis shrimp as well.
Did you anchor the seaweed down at all? One of the seaweed clips they sell will work, as will rubberbanding it to a rock or even wedging it a bit between the rock