[Michael Hoaster]

I read the study on thalasia in Puerto Rican waters. In it there was a good chart of sediment composition in different areas. So yes, not a whole lot of mud in there. I wish he had discussed it a bit more. The seagrass article from Chuck's Addiction had some really informative discussion on the application to our tanks, plus a good quote from Ron Shimek:

"Sediments - The seagrass refugium's sediment is vital to the health and long term survival of the seagrass just as it is in natural meadows. How you construct the sandbed is going to determine its functionality in providing a nutrient rich environment for the seagrasses rhizomes and root structures. Seagrasses are plants that depend upon their roots for the uptake of nutrients, roots that require extremely fine grain sizes, it will be imperative that a calcium carbonate substrate with grain sizes ranging from 0.2 - 1.02mm be used with a depth of no less than six inches, deeper if possible. Incorporating a live mud into the sediment during the sand beds construction will ensure a suitable number of infauna are introduced. Just as in nature the infauna are critical to the functionality of any sandbed to process nutrients and prevent the formation of sand clumps by their movement through the sediment (Shimek 2001)."