I would not just dump it in, put it in a container like mentioned... or just skip it. I used it years ago and never noticed anything positive from it. I had an algae issue years ago and cant say 100% it was the mud but when I removed the mud it started to go away. I believe over the 2 years I had it in the fuge it trapped a bunch of stuff like a sandbed can and started to break down in there which dumped the nutrients back into the tank....
And let me tell you when I was cleaning it out not only was it hell getting the mud out and wiping everything down but it smelled like death. Never again for me