From everything I've read, if the fuge is small thent he use of sand and LR
is minimal, especially sand as it requires a deep bed to be effective. When I get mine up and running, I'm not going to use any sand or mud and toss in whatever LR
rubble I have left laying around in my tank just to get it out of there and keep it alive. I have just started reading, but there has been some backing that I have seen in these forums...hopefully they'll speak up and give some more detailed information.
Basically, if you have spare LR
then I would toss it in, if not I wouldn't worry about it unless you aren't currently running 1-1.5x LR
per gallon...in that case you should put it in your DT. No sand or mud, just macro of whatever you choose.