The manufacturers of Miracle Mud designed it as a substrate for sumps and refugiums. Saltwater aquariums often use sump filters—filters with a large volume of water in a separate sump to increase the water volume, provide filtration and provide an area to attach various aquarium equipment out of sight. Some sumps also contain an area called a refugium, an area where beneficial organisms can breed undisturbed by fish. Miracle Mud's alleged benefits include breaking down toxic nitrogen compounds and adding various minerals to the water when added to a sump or refugium.
What Is Miracle Mud?
Miracle Mud consists of a commercially prepared substrate—a mud. Oceanic mud, harvested from the ocean floor, comprises roughly 80 percent of the material. This oceanic mud is subjected to various heat and chemical treatments to change its properties. Various minerals and other supplements comprise the rest of the substance. The minerals slowly leach into aquarium water, providing calcium and trace minerals for invertebrates like corals.
Several types of refugiums exist, but an in-sump refugium works very well for substrates. Since sump filters have a major DIY element to them, many of the specifics will vary based on your exact designs. However, certain general guidelines will hold true. First, you will glue two acrylic or glass pieces into the sump to create a box. This will be the refugium itself. Ideally a refugium should take up at least 10 percent of the sump volume. The refugium needs a depth of at least 2 inches to accommodate Miracle Mud.
How Much Mud?
The manufacturer recommends that you create a substrate bed at least 1 inch deep out of your Miracle Mud. The extra inch of the walls makes sure the Miracle Mud does not spill out of the refugium and into the rest of the aquarium. The manufacturer estimates that 5 pounds of Miracle Mud will suffice for aquariums up to 65 gallons in volume. The manufacturer's website also has a chart for aquarium volumes beyond this.
In with the New
The manufacturer's instructions state that you should swap out 50 percent of your Miracle Mud per year. This replenishes trace minerals and elements in the substrate. You should not replace all your Miracle Mud at once, since substrates foster the growth of beneficial bacteria that break down biological wastes. Replacing all the Miracle Mud at once could mean losing these beneficial bacteria.