[Here's just a little read by Ronald Shimek, Ph. D. The entire article is here:
http://www.rshimek.com/reef/sediment.htm
"Problems:
More imagined than real problems bedevil keepers of sand beds. The imagined problems are proposed by people who are ignorant of the sand bed dynamics. Among these imaginary problems are accumulations of hydrogen sulfide and detritus, and the need for sifting. Hydrogen sulfide will indeed be formed in the lowermost layers of a deep sand bed. It will NOT migrate up through the sediments to poison a tank. Hydrogen sulfide is an amazingly toxic gas, but that toxicity is exceeded by its pungent rotten-egg odor. The gas will have an exceptionally strong odor, and will seem overwhelming at levels well BELOW toxic amounts. If you can smell this stuff without it literally taking your breath away, it won't be at a harmful concentration. There is no real evidence to indicate that it may reach toxic levels in a deep sand bed.
Detritus build up in the sediment is another non-problem. If the sediment fauna is thriving, there will be a slight build up of fine detritus while the rest will be processed by the infauna. The final imaginary problem, the presumed need for sifting in a healthy sand bed, simply does not exist. Small organism movements "sift" the sand sufficiently. Any other sifting of a healthy bed will cause serious harm.
Sand beds recycle materials and export many of the excess nutrients in an aquarium. Some excess nutrients are mobilized by becoming soluble through metabolic processes and need to be exported either as harvestable macroalgae or animals, grown in the main tank or a sump.
The only real problem with a sand bed is the reduction in diversity as the bed ages. This is caused by extinction and replacement problems because the volume of our beds is simply too small for some species to generate self-sustaining populations. This is remedied, by purchasing a detritivore or recharge kit or two every year or so to give a boost to the fauna.
Conclusion:
The installation of a live sand bed is easy, straight-forward, and inexpensive relative to almost all other aquarium purchases. Once established, such a bed will contribute much to the success of a reef tank by providing a biological filter with sufficient capacity to for most tanks. Additionally it will provide food for many of the suspension feeding animals such as small polyped stony corals. And, it will do this all with a minimum of care and expense."
As with just about anything in reef keeping, what works in one tank is not guarenteed to work in another. There are many ways to keep a successful reef tank so choosing your own method is up to you.]