Tank Problems - Please advise

carlsburg

Junior Poster
Dec 8, 2007
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I've had a 20gal fully planted tank setup for 5 months now, and the tank spent its first 3 months with no fish. I found its easier to just worry about the plants and getting algae under control before adding fish to the equation. About a month ago I started stocking with algae eaters and added 4 otos first, then a week later 10 amano shrimp. On Saturday I found some really beautiful long finned zebra danios and put 6 of them into my tank. Monday night my tank was crystal clear and everything seemed great. By Tuesday night the tank had turned a translucent milk color and smelled like sulfur. All my shrimp died by the time I came home from work and noticed the problem. I immediately did back to back 50% waterchanges for the last 2 days, and while the tank is starting to look a little better, it smells to high hell still. Is this just a bloom of bacteria, and will it go away on its own? Any ideas as to the cause? The tank utilizes pressurized C02, EI dosing, 37W of PC lights and a Rena XP3 canister filter with lots of filter floss. Any advice? I'm hoping I can salvage the situation, only 4 danios and 3 otos remain.
 

ShadowMac

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Mar 25, 2010
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sulfur smell is not a good sign. Biollante on this forum often asks if you notice bad smells, rotten egg like (sulfur). He is a smart guy as are many others here (like this Tom Barr guy who is like the Chuck Norris of aquatic plants. Say his name and plants grow better) so they could probably help you better than I, but I will try anyways and be corrected if I'm wrong. (just in case i get eaten by the evil plant monster :p to clarify I'm a smart guy too, but not as experienced as many others and leave the really techy stuff to other more knowledgeable individuals and plant monsters)

from my understanding sulfur smell is a sign of anaerobic bacteria. sulfur gas created by the bacteria gets trapped in the substrate and when suddenly released can cause sulfuric acid in the water. Any fish gasping at the surface? Did you move anything around? stir up the substrate at all? this shouldn't be a problem in a planted tank as plant roots oxygenate the substrate well. I had this happen, without the clouding when I suddenly added plants to a tank that had never had plants and been going fine for over a year. The substrate was anaerobic in areas and killed a good number of my fish. I thought they were sick, so I worsened things by treating the tank. If you have another tank I would move them there until you can stabilize the 20 gallon. you could probably get a 10 gallon for cheap ($15) throw an air stone in it and keep your fish alive until you worked out the problem.

ps. the reason for the chuck norris reference? its his birthday. God said "let their be light" and Chuck Norris said, "Say please".
 

Cyclesafe

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Jan 19, 2011
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The rotten egg smell is caused by anerobic bacteria generating hydrogen sulfide gas. H2S is detectable by the human nose at very low concentrations, that's why its used as an indicator in otherwise odorless natural gas. Very toxic at higher concentrations.

The milky water may or may not be associated with the anerobic bacteria. But either way, repeated water changes and good circulation are the fixes. One time I got impatient and used erythromycin which worked quickly and didn't mess up the other biology in the tank.
 
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pepetj

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Oct 8, 2008
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It could well be that your fish and shrimp died out of CO2 poisoning and the rotten egg smell was due to decaying biological tissue. If you have a planted tank with healthy and strong root systems embedded in the substrate I doubt hydrogen sulfide would be present in dangerous, let alone lethal, concentrations. Following the H2S line of thinking, maybe your canister filter malfunctioned to a level of turning into a denitrator? I have no clear idea of what happened... maybe contaminated food killed your inverts and fish, maybe too much cooper, a faulty heater... I just can't point my finger here comfortably in any direction.

Based on what I've learned I would rule out CO2 poisoning first.

Whatever happened, a spike in ammonia/ammonium due to decaying dead inverts and fish likely induced a bacterial or algae bloom (or both). I would just perform as huge as possible water change and check every component of the tank; it's not uncommon that more than one factor end up causing problems. In moments like this, if I don't have a spare seeded filter from a healthy tank to install in the fouled tank then I would consider adding biological filtration enhancement products, no matter if based on heterotrophic or autotrophic bacteria or both.

Pepetj
Santo Domingo
 

fjf888

Guru Class Expert
Oct 29, 2007
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ShadowMac;63201 said:
(like this Tom Barr guy who is like the Chuck Norris of aquatic plants. Say his name and plants grow better)

So that's the key, I knew I was missing something ;)

If Tom is the Chuck Norris, who is the Steven Seagal? I have one person in mind actually.

Back to our regularly scheduled programming.....

CO2, perhaps lack of O2. If you are using certain CO2 regulators and needle valves you could have been hit by the End of Tank Dump (EOTD), and gassed all the fish. With little surface chop and possibly the tank cycling with the addition of fish (biofilter bacterial are not stagnant) and NH4/NH3, to NO2 and NO3 reactions could have sucked up a lot of O2. I kind of have a hard time with H2S as well.
 

nipat

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May 23, 2009
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May be there was an electricity black-out that made the filter rot and killed the critters?
 

carlsburg

Junior Poster
Dec 8, 2007
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situation

I don't think the deaths caused the event, rather the event caused the deaths. The tank still stinks to high hell, but its getting much better. There are white stringy particles hanging on the surface of all the plants, inside the filter tubes ... etc. Its definately a bacteria bloom, but i have no idea what triggered it. The tank is densely planted to the point that almost no gravel is exposed, and I haven't disturbed it. Nothing new happened to the tank other than a very light feeding of the zebra danios. Its not a CO2 issue, drop checker still shows green at the end of the CO2 cycle. Very strange. In my 10+ years of keeping tanks, never seen anything like this before. Ah well ... live and learn.
 

Cyclesafe

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Jan 19, 2011
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San Diego, California
According to Wikipedia Humans can detect H2S at 500 parts per trillion. I wouldn't wonder that you'll need many water changes to eliminate the smell - even assuming that H2S is not still being generated. I dunno, if it were me, I'd consider nuking with Erythromycin.
 

carlsburg

Junior Poster
Dec 8, 2007
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Yeah i may just have to do that ... then spent hours vacuuming the tank and scrubbing the filter. And just when my tank was really starting to look good.
 

carlsburg

Junior Poster
Dec 8, 2007
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tank

Yeah the nuking began ... lots of the plants are dropping their leaves and going transparent ... not sure if most of my staurogene and rotala is going to make it. Ah well ... at least its a good excuse to goto Aqua Forest in SF and do some rescaping.


I'm tempted to just trim the staurogene back pretty harshly ... they seem to still have well established roots and may grow back.