Well I don't use fiji mud in my system so I can't give you a great deal of info. From what I have read there are pros and cons to the "muds". I believe that for it to be effective you have to have a very deep bed of the stuff 6"+.
The miracle mud/fiji mud along with a DSB
are topics that have people strongly divided. I personal have a minimal DSB
meaning that my sand bed is as much as 6" deep in areas of my tank and 2" deep in others. Good filtration is going to come from lots of LR
a good skimmmer and the use of a refugium. The sand is just one of those things that remains up in the air. Some people will tell you to go with a bare bottom tank and others will say you have to have a DSB
. I think that if I were going to use one of the muds I would use it in my refugium only and have a 4-6" sand bed in my main display. My system has been up and running for 3 years now and I have few issues with it.