Hydrogen Sulfide in Reefs

[piranhaman00]

Hello,

I have been using an anaerobic reactor to heavily reduce nitrates, it works amazing but I am having troubles dialing it in. Most of the time, the effluent is 0ppm nitrate but there is a definite detectable sulfur odor, which I presume to by hydrogen sulfide. This is only evident in the effluent not the tank water.

Is there negative effects to this? I have not noticed any effects in my aquarium, although it’s a 450 gallon system so there may be a very slow buildup. Would carbon remove it if necessary?

Thanks

 

[Randy Holmes-Farley Verified Community Expert]

Hydrogen sulfide is quite toxic, but it can also be detected by smell at fairly low levels.

Hydrogen Sulfide and the Reef Aquarium by Randy Holmes-Farley - Reefkeeping.com

 

[Enderg60]

When I was running a sulfur reactor for nitrates there were times the feed would clog a bit and the tank would start to smell a bit. I would just adjust the effluent rate and run some carbon and the smell would be gone in a few hours. This happened 2-3 times a year and I never saw any negative effects.

That said, listen to randy over me.

 

[piranhaman00]

Hydrogen sulfide is quite toxic, but it can also be detected by smell at fairly low levels.

Hydrogen Sulfide and the Reef Aquarium by Randy Holmes-Farley - Reefkeeping.com

Thanks, per this write up H2S is metabolized in the reef so it theory the H2S could be degraded before reaching dangerous levels?

 

[Randy Holmes-Farley Verified Community Expert]

Thanks, per this write up H2S is metabolized in the reef so it theory the H2S could be degraded before reaching dangerous levels?

It might be.

 

[piranhaman00]

Hydrogen sulfide is quite toxic, but it can also be detected by smell at fairly low levels.

Hydrogen Sulfide and the Reef Aquarium by Randy Holmes-Farley - Reefkeeping.com

Read through the article again, what about if I passed the effluent containing H2S (by smell) through a reactor containing GFO? If this was to work would the effluent then contain no smell? The internet says elemental sulfur does not smell and only H2S has the rotten egg smell. Would this work?

I’ve also been dosing iron to assist in breaking down the H2S.

 

[Randy Holmes-Farley Verified Community Expert]

Yes, the smell will decline or disappear if flow is not too fast.

 

[piranhaman00]

Yes, the smell will decline or disappear if flow is not too fast.

Excellent , I routed the effluent through a reactor containing a mix of carbon and gfo, very slow flow to run the anaerobic digestor, effluent through reactor has lost all egg smell. Hoping it lasts awhile before exhausting.

Any ideas on the longevity ?

 

[Randy Holmes-Farley Verified Community Expert]

It may last a long time as it is a catalytic process as opposed to a binding process as with phosphate on GFO.

 

[GARRIGA]

Rumor has it that if one loses power using a canister filter for several hours that hydrogen sulfide could form thereby killing all inhabitants when power returns if one doesn't clean the canister by removing the water inside. I had a canisters and UG filters that would often experience loss of power including one which lasted three days. Not knowing the threat. Didn't bother doing anything about it. Therefore, is this old wives tales or valid and perhaps when turned back on since both filter types effluent near the surface then perhaps the filters gassed off any harmful contaminants caused by the power outage. Curious to know.

 

[pixelhustler]

Rumor has it that if one loses power using a canister filter for several hours that hydrogen sulfide could form thereby killing all inhabitants when power returns if one doesn't clean the canister by removing the water inside. I had a canisters and UG filters that would often experience loss of power including one which lasted three days. Not knowing the threat. Didn't bother doing anything about it. Therefore, is this old wives tales or valid and perhaps when turned back on since both filter types effluent near the surface then perhaps the filters gassed off any harmful contaminants caused by the power outage. Curious to know.

Unfortunately, I have answers for you all on this matter. I had my sulfur denitrator clog for several days and once unclogged, the smell was noticeable but went away after a few hours with no ill effects. I always increased oxygenation when this happened for good measure. I loved the denitrator and it’s one of the most effective pieces of equipment I’ve used, although it tends to bottom out my phosphate for reasons I don’t understand.

This morning, I hooked up a sulfur denitrator I had not used for a couple of months. I let water flow through it separately for an hour or so, but the H2S buildup must have been really high. I should have thoroughly rinsed it and it was stupid to overlook this. Within 30 minutes of install, I noticed the smaller fish (yellow clown gobies) swimming erratically. I did 2 large water changes and increased oxygenation immediately but it was all too late. My clownfish and small tang are still alive but I’m not sure they will make it. I’m all out of water, and have a bunch of pumps oxygenating, so all I can do is wait and see. My corals look unbothered.

 

[GARRIGA]

Unfortunately, I have answers for you all on this matter. I had my sulfur denitrator clog for several days and once unclogged, the smell was noticeable but went away after a few hours with no ill effects. I always increased oxygenation when this happened for good measure. I loved the denitrator and it’s one of the most effective pieces of equipment I’ve used, although it tends to bottom out my phosphate for reasons I don’t understand.

This morning, I hooked up a sulfur denitrator I had not used for a couple of months. I let water flow through it separately for an hour or so, but the H2S buildup must have been really high. I should have thoroughly rinsed it and it was stupid to overlook this. Within 30 minutes of install, I noticed the smaller fish (yellow clown gobies) swimming erratically. I did 2 large water changes and increased oxygenation immediately but it was all too late. My clownfish and small tang are still alive but I’m not sure they will make it. I’m all out of water, and have a bunch of pumps oxygenating, so all I can do is wait and see. My corals look unbothered.

Was the effluent gassed off at the surface? Trying to understand why in my situation there were no losses or apparent ill affects after prolong power outages? Something that living in south Florida is unavoidable due to storms or just outdated power grids. Why my main build won't go up until reliable backup solutions in place.

 

[Randy Holmes-Farley Verified Community Expert]

GFO can tend to help in hydrogen sulfide scenarios. More organics in the water make it develop hydrogen sulfide faster.

 

[pixelhustler]

Was the effluent gassed off at the surface? Trying to understand why in my situation there were no losses or apparent ill affects after prolong power outages? Something that living in south Florida is unavoidable due to storms or just outdated power grids. Why my main build won't go up until reliable backup solutions in place.

I think it takes quite a while for hydrogen sulfide to build up to dangerous levels. In the past, when it eventually clogged and didn’t run for several days, I would unclog it and run it with the tank right away with no issues, even with the rotten egg smell.

This time, it was sitting in storage for a couple of months full of water. I let it cycle in the sink and the smell wasn’t stronger but it did last much longer. When I opened it to fully rinse it (after poisoning my tank) the water at the very bottom was grey with black specks, similar to a deep sandbed that goes anaerobic. I should have disassembled it and fully cleaned in instead of just letting water run through it in the sink, which clearly didn’t cycle out the buildup at the bottom.

Still, I lost a Kole tang and two yellow clown gobies but my clownfish, royal gramma and corals look completely fine. Very sad but I was very negligent. Lesson learned.