The following is a cut&paste from numerous articles, FAQs located at wetwebmedia.com...
Sugar-fine grade... excellent for denitrification and deep sand bed (DSB) strategies seeking natural nitrate reduction (NNR). Ideal at depth for culturing seagrasses like Syringodium and Thalassia. Very supportive of capillary root structures in red mangroves (Rhizophora mangle). Encourages the finest zooplankton (like copepods) to develop in refugia. Ideal substrate for free-living corals like Fungiids (stony mushroom, plate anemone, slipper, tongue and helmet corals), Trachyphyllia (Open brain coral), Goniopora stokesii (Green Flowerpot), and Catalaphyllia jardinei (Elegance). This is the ideal grain size for most detritivores and sand sand-sifting reef animals.
* Note: you must be mindful too of the fast rate of dissolution of some sand beds. In most healthy systems, fine aragonite has a "half-life" of 18-24 months. That means that after two years, perhaps, a 3" sand bed will have been reduced to 1.5" and possibly failing in its duties (another unheralded cause for the unfair criticisms of mismanaged DSBs). For this reason, aquarists seeking optimum nitrate control are advised to resist being frugal and apply honestly deep sand beds, and adding more substrate as necessary in time
RE: DSB Crash
Yes I did - and I could have missed it I guess, but I was attempting to address the SPECIFIC issue of the lifespan of a DSB being 2-3 years and then it crashes, killing everything in the tank. Is this true?
(Not in my experience. I am a fan of monthly "stirring", annual replenishment (including upper layer disruption) of such substrate arrangements though)
I mean it does kind of makes sense I guess sense all that waste has to go somewhere... is there some method of cleaning it to extend the lifespan?
(Oh! Yes... as stated, though I would not thoroughly gravel vacuum the substrate, I would stir it with a dowel (wood or plastic) on a regular basis, and add more material to it every year (you'll find it "goes away" as in dissolves over time).)
Sorry for the trouble
)
(Me too. No worries. Just trying to get to an answer.)
With the above being stated one must remember there is more to a DBS than simply dumping in the sand. Proper aquarium husbandry including but not limited to - proper water flow, slight occasional stirring of surface, protein skimming, replenishment of dissolved sand etc must take place.
In the end it's up to the individual aquariast. From the hours of research I've done I'm more than satisfied that a DSB, with proper maintenance provides tremendous bonuses to a Reef Tank with no chance of crashing.
Rookee
