Eric Borneman, noted coral pro, on Miracle Mud:
Let it be known officially that I strongly dislike the system - not so much that it works or doesn't (because almost anything can be made to work), but that those marketing it, making it, using it, and reviewing it have, to my knowledge, very little inkling of any of the issues surrounding it - and to me, that makes a sham, par excellence. One didn't need to know the composition of this substrate to make some very accurate suggestions about its use - as I think I did several years ago in a FAMA article called "Demystifying Mud."
Of course, my response here is hypothetical to your well pointed question and also hypothetical in that I have never used Magic Mud - nor do I plan to use it. The high iron content is obviously indicative, as we all well knew, of a terrigenous sediment. So the algae he uses (also a weak point using Caulerpa) grow well. The nitrates being produced by the bioballs similarly fuel algae growth. Mud, by definition, is a mixture of sediments classified by size and organic content. The organic component, being once living biomass, contains higher amounts of nitrogen and phsophorous...also encouraging algae growth. Eventually, this organic component will be used up, requiring more to be purchased all to the $$$ of the company and its suckers...err...customers. That, or you'll have a mixed siliciclastic sediment similar to putting playsand in the refugium. Why would you add more organic content to a closed system that, as a rule, is already magnitudes of order higher in organics, necessitating the use of skimmers and carbons to deal with it? I dunno. The reason its effective? Because you have a microbially productive sediment community, similar to carbonate muds in lagoons and seagrass areas. You have uptake via, admittedly lame, macroalgae. Sure it works. So does the same principle using sand, and probably more effectively in the long term. After all, if coral reefs thrived with high terrigenous inputs, you wouldn't see the amount of study being done to look at the effects of terrestrial nutrients and sediment loads degrading reefs worldwide. Duh.
The result to corals and zoox? Probably in most species, higher linear extension of a less dense skeleton, lower rates of calcification, and higher densities of zooxanthellae...possibly too high considering the light levels some expose them to, possibly lowering bleaching thresholds artificially.
Please note that I too have never and will never use this stuff. I suspect it is basically laterite, a great freshwater substrate, which would not be found on a reef. There are MANY effective ways to run a refugium, many with similar results (but no "testimonials"). Cheaper, as effective...possibly more natural. IMO, that is the way to go. I am cheap
If you like it, so be it. But I DO NOT want people thinking it is a "miracle" and will get them out of a bind, or that it is in any way necessary to running an effective system.
