Originally Posted by bohmert
Amen Reef! I for one wasone of thise people had my tank up or couple months and decided sand looked like crap so I went in moved everything including stirred the sand up etc. Guess what.........
How deep was your sand bed when you did this? What kind of sand was it?
What happened to the tank?
The only time I ever had a problem with hydrogen sulfide was when I was real new in this hobby. I had an algae problem and took almost all my rock out of my 46 gallon and left it in 5 gallon buckets to kill the algae. I didn't know that I needed to keep flow in those buckets, and when I got home that night I smelled rotten eggs in living room. It was disgusting.
On the other hand, when I switched over from my 46 gallon to my 150 gallon, I took my 4" sand bed out of the 46 and scooped it right into the 150. No rotten egg smell. The substrate was fine enough that the microfauna was doing its job of converting nitrates to nitrogen gas. Fine granular sand does the best (between 0.05mm and 0.2mm) for harboring the correct bacteria to convert nitrates to nitrogen gas.
The reason that there is so much fear around hydrogen sulfide is in relation to the old "plenum" style filtration (this was an space under the substrate that was very low in oxygen and harbored anaerobic bacteria that would convert nitrates into nitrogen gas, which leaves the system naturally). Hobbyists used to use an undergravel filter base with a crushed coral substrate (the crushed coral is coarse enough particle size to allow water to pass through to the plenum (that undergravel filter base). The problem was the hobbyists wouldn't always clean the crushed coral and it would essentially get "clogged" and therefore the area underneath (the plenum) would start to "rot". This would form hydrogen sulfide and when the hobbyist finally decided to clean the substrate, the tank would be filled with it almost immediately.
Deep Sand Beds, when done correctly and because of their small grain size, are a much less likely culprit for the formation of hydrogen sulfide. In this article
by John Cunningham in Aquarists Online
, Deep Sand Beds are further explained and in this article
by Ron Shimek, common DSB myths are debunked.
I am moving the discussion of Deep Sand Beds to its own thread as not to highjack the Original Poster's (Frighty Dog) thread.