Hydrogen Sulfide - a possible problem?

[Accipiter]

Advanced topic? Guess so.

I'm planning my new aquarium right now. (Actually, it's my first one!)
No sump included, strange, but true. Since I'm aiming for an easy setup with a low bio-load, I consider it sufficient enough.

However, the plan may fail! Because, the setup involves a DSB (in the main tank. no sump.) What frightens me is the fact that DSB produce Hydrogen Sulfide, which may be toxic in certain amounts, though not the once we meet in the aquariumhobby(?). What really frightens me, is the hydrogen sulfide's smell!

According to Ron Shimek: "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."
Does this mean I actually might get a problem regarding the sand bed's smell?

He continues: "There is no real evidence to indicate that it may reach toxic levels in a deep sand bed."
What does this mean? Is there a possibility that the dsb might generate toxic levels of the gas?

Thank you very much!

Regards
Accipiter (17 years, Norway)

 

[Randy Holmes-Farley]

It is very unlikely to be toxic to you, if that is what you mean. You will not regularly be digging around in anaerobic sediments.

I discuss hydrogen sulfide issues in great detail here:

Hydrogen Sulfide and the Reef Aquarium
http://reefkeeping.com/issues/2005-12/rhf/index.php

FWIW, there was no evidence of any H2S formation in the deep sand beds I kept for many years. That comment is based on lack of smell or black deposits on removing the beds. That doesn't mean it cannot happen, just that it need not happen.

 

[Accipiter]

Really, I were wondering even more about if it's possible to smell the H2S, even if I'm not disturbing the sand bed (I know it probably would smell when/if I remove the bed). You see, it won't be that pleasant with a rotten egg-smell in our living room.

(Btw, the tank is a 92 gallon corner with open top. if that matters)

 

[Randy Holmes-Farley]

I've never heard of anyone notice the smell of hydrogen sulfide specifically unless they stirred up a stagnant sand bed. Reefs have various smells from organic compounds that might mask very faint H2S odors, but this should not be a concern.

 

[Accipiter]

ah, now I become relieved, and I won't need to abandon my plan! Thank you!

 

[Randy Holmes-Farley]

:thumbsup:

Good luck.

 

[Accipiter]

Thank you, I've been looking forward to this

 

[reefgal]

I have a DSB that has been in my 220 gallon tank since 1999. Many people assume that any black patches in their sand is H2S. However, most of these patches of black sand turn out to be cyano bacteria. I tested several patches of sand in my tank and refugium fearing H2S, but absolutely none was detected by the test kit. Nothing but harmless cyano bacteria. If a DSB is set up properly and fed and maintained properly, it should never become a problem.

 

[Randy Holmes-Farley]

Patches of gunky stuff on the surface certainly may be cyano, but blackness that extends below the surface to dark areas inside the sand is very likely to be metal sulfide deposits. I don't know if they would be detected by whatever kit you used.

 

[3D-Reef]

Just curious here.Isn't it the cyanobacteria in the sand,being No3 limited, that is producing H2S or S2?And wouldn't any sample as soon as it was brought up from the sand,exposed to the water column,oxidize the sulfide back to sulfate?

 

[Randy Holmes-Farley]

Isn't it the cyanobacteria in the sand,being No3 limited, that is producing H2S or S2?

I don't know of a reason to assume it is cyano that is causing formation of H2S. I'd rather expect different species, especially in nonlight areas, like under sand.

And wouldn't any sample as soon as it was brought up from the sand,exposed to the water column,oxidize the sulfide back to sulfate?



Eventually, much of it is oxidized, yes. But not quickly enough to prevent potential smells or toxicity to marine organisms.