New Tank with Sulfur Smell

[Axle86]

A couple of days ago I got my 55 gallon setup with Fluval Stratum and also got some "Natural Creek Stone" I got from Home Depot, thought it would be a money saver, look neat against the black background and substrate. I did rinse and clean the rocks. However, after 2 days have gone by I am noticing a sulfur smell. I've never used Fluval Stratum before but I also don't think that's where the smell is coming from. I have a feeling it is coming from the rocks. Someone had suggested I boil/bake the rocks but I do have a concern about explosions and not sure that would necessarily fix the problem--but then again I don't know. 

The tank is not stocked with any fish and won't be until likely after the holidays.

Other concerns about the rocks, because hindsight is 20/20, is whether or not the rocks will alter the water chemistry, hardness, etc over time. I plan on doing a large school of neon tetras and possibly other fish that prefer similar water parameters. Haven't completely decided on everything.

My gut instinct is to remove the rocks and find a new purpose for them, after all once plants are taking over the tank I probably won't see much of the bottom anyway. I don't know what type of rock these are other than they're natural creek stone and not cement. 

I guess the first question is to rule out the possibility that the Fluval Stratum would be the cause of the smell? Second is the likelihood of these rocks being an issue. I'm not opposed to removing the rocks but wouldn't mind not having to remove them either. 

 

edit: The water parameters after 24 hours after filling were:

pH  6.6, GH 72 ppm, KG 36 ppm, Ammonia 1 ppm, Nitrite 0 ppm and Nitrate >0 but less than 5 ppm. I rechecked the water and nothing has changed (that I can measure).

Edited November 8, 2020 by Axle86

[Maggie]

Just my opinion that its not the Fluval product since that would be made for aquarium use. 

[Axle86]

24 minutes ago, Maggie said:

Just my opinion that its not the Fluval product since that would be made for aquarium use. 

Yeah that's kind of the feeling I got...but since I've never used the stuff before. At any rate, I went ahead and removed the rocks. Probably the better choice rather than to experiment with boiling and baking rocks and finding out they're not safe for fish. I'll probably wait until tomorrow but I should probably change out some of the water and do so until the smell is gone. 

[Dandy Pearl]

So this smell was detected after a few days with doing nothing to the tank? No water changes or any thing? Just the filtration and airstones running?

If so, this is a puzzler.

I think you did the right thing of removing the 'unknown' rocks.

 

[Axle86]

@Dandy Pearl That is correct. Actually just a HOB and heater. The tank is new, I did have it going, temporarily, with fish a month ago. I drained it and it sit for a few weeks dry. I rinsed the tank out before filling it and adding substrate and this "creek stone"

The best I can determine on these rocks is that they're supposed to have come from a dry creek bed...but of course not knowing what kind of rocks these are, or if they've been treated with something (nothing on the package)...Hopefully a drain and refill will fix the problem and won't be a problem later on when I do get around to adding fiash.

[Raeburn]

Hi. Have you added any chemicals to the tank that may be the source of the smell? The dechlorinator I use smells sort of sulphur-y.

[Axle86]

Nope, didn't add any dechlorinator. I am on well water, however, I've never noticed any sort of odor coming from the water. I did see that Prime and some other stuff can cause odors. I did try to search around to see if Stratum might cause an odor, same for the rocks (I was inundated with ads to go buy some more rocks). I did see a lot of posts on other aquarium related sites that rocks from places like Home Depot are allegedly safe or that people didn't have problems. Couldn't really find anything mentioning a sulfur smells specifically for Stratum or much of anything about the rocks. 

I guess the one way for sure I'll know having taken the rocks out of the tank (and now I can put ~3 more gallons of water in) is to drain and refill the tank and see if the odor comes back. Probably need to ring out and rise the filters too.

I'll post back to the thread after I've done that and a few days have gone by. Definitely curious if anyone has had odd experiences like this.

 

[JaredL]

It's possible bacteria in your tank is causing sulfates to break down causing hydrogen sulfide which smells like rotten eggs.

Edit: I'm no expert on this. Just got curious and googled some info.

Edit: it looks like this can be a problem when there is a lack of oxygen available. Does your filtration agitate the surface adequately? Are you using an airstone?

Edited November 9, 2020 by JaredL

[Axle86]

@JaredL Yeah I read similar things and most of what I read sounded like that is more likely to occur in an older setup tank or having deep substrate. No airstone in the tank currently, however the tank is completely new and was filled along with the Fluval Stratum and rocks then the smell started at about 48 hours in. To answer your question, no there is likely not adequate agitation if I had fish in the tank, right now it is just water, substrate and a few plants from my other 10 gallon. My guess would be that since the tank is not stocked that oxygen levels should stay at a decent level with the agitation there....then again I'm not expert either. 

I did drain and refill, rinsed out the filter media and we'll see what happens. If it stinks again in a couple days then we'll know the rocks from Home Depot weren't the cause...or maybe I didn't get all the water out (which is pretty much impossible having substrate)...

[Axle86]

Looks like I forgot to follow up so here's an update. The smell was definitely the rocks. Not sure if it would have caused problems but felt it would better to not roll the dice. In short, I removed the rocks, changed the water out and no more smell. I've had the tank running with fish since then and haven't had any problems so far. 

So the moral of this story is don't put random rocks in your tank unless you know the source or know what kind of rocks they are. Same goes with DIY driftwood, that was something else I thought about doing and didn't go through with. It is very easy to add stuff to the tank that might cause more problems.