This is my most recent video of my fish room. I am in the process of improving my fish room.
Fishguy1978
m.youtube.com
I have weldon 3 and 16 AND a free acrylic 120 and a fish room with a floor drain What could possibly go wrong?The brown stuff is probably where water was able to penetrate the joint and algae has grown in the joint.
I would be cautious.