Unusual Problem with Nitrite Spikes and Low Oxygen Levels

[joachimsim]

Guys,,,maybe u can help me out with this one!

I have a 2 FT community planted tank>....Recently...think 2 days ago...I had a problem with the tank...incurring deaths of 5 fishes...4 neon tetras and one SAE..heart pain!

2 days ago..I think I accidentally pulled out the plug on the lighting for the tank and hence..it wasn';t till in late afternoon that I switched on the lights...On observation before feeding...and after switching on the lights...I found the tetras dead...and the rest of the fish like mollies and others Gasping for air at the surface and respiring very....quickly...even my Yamato shrimp was unusually at the surface/..!

On instinct...I tested the No2 level which were dangerously high at 1 mg..and No3 levels within acceptable level at 25mg. I did a Oxygen Test at it was between 2 to 5 mg...which was very low ...

I did a 30% water change and the Next morning I discovered my SAE dead as well..it was previously...respiring very quickly near the surface as well..
I did another No2 test and found that it was still high...after the water change...I do not know whether I did another Oxygen test....but I assumed it was low...and Guess somehow the nitrogen cycle had been disrupted due to lack of O2 maybe?? so I aerated the water the whole day...despite the fact that It was a planted tank and the Lights were On...

On inspection this morning...I found the fish to be more comfortable..however on checking the NO2 levels...it was still very high! My other 2 Feet planted tank with 2 parrot fish...4 mollies 1 Pleco and 1 SAE with a small sponge filter....even after cleaning in aquarium water still registers less than .2mg of Nitrite with no water change!!

Hence I did another water change today and cleaned up the External Canister filter...with filter wool and bag of ceramic rings....Nothing was amiss...and I never cleaned the Rings with Tap water...just replaced the wool put back the filter box into the canister again. THe filter wool was quite dirty..but I had this before after cleaning it after 3 to 4 weeks..without this NO2 and o2 problem before!!

Can somebody pls tell me what went wrong..and what is wrong?? From my own Diagnosis...the NO2 spike was caused by a disruption,...possibly due to the few hours that the lighting was off...it caused the plants and fish to respire and fight for o2..resulting inthe in the bacteria not having enough 02 and dying....?? hence the cause for No2 to shoot up and not No3....Even with water change its still registered above 1 mg!! very dangerous high.

BUt on the other hand...I had times where by I forget to switch on the lights and no such deaths due to the disruption occurred before.

Another reason..could be due the a clogged filter wool compartment in the filter..BUt then again...I had times where by I cleaned the filter wool less often then recently..my last filter clean up was 1 or 2 weeks ago...and its quite a big canister filter to use for a 2 ft tank. Surely...it can't be clogged up until the bacterial all died....due to lack of Oxygen? And aren;t there....other bacterial sources in the substrate as well???



One more thing.....
Anyway..I like to ask....with the exception of using a External Filter with a Skimmer..How do u remove and prevent surface Scum from forming with other filters in a small tank like a 2Ft or smaller??

[bclee]

Few questions:
How old is your tank?
Any CO2 injection?
Any chemical/medication/additives added prior to the incident?

My take on what happened. Something might have wiped out the nitrifying bacteria before the whole incident. The N-cycle may have broken down. But your plants are helping to consume the NH3.

When your lights did not turn on, the NH3 level rises causing a NO2 spike.

When NO2 poisoning happened:
- Make BIG water change, 50% or more
- Add some salt to alleviate the NO2 poisoning
- Aerate the water
- Continue water change daily(for more frequently) until NO2 is down to a safe level.


BC

[joachimsim]

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On 4/1/2003 3:41:12 PM

Few questions:
How old is your tank?
Any CO2 injection?
Any chemical/medication/additives added prior to the incident?

Tank is old enough to be fully cycled...since Oct last year I think..I inject DIY co2..although the las few days or week..I think the supply has run out...This is not the first time...Need to replenish my sugar and yeast again. Yeah I did add Medicines..for White Spot and Internal Bacteria before..but its weeks ago...and I Think I have already done water change prior to this INCIDENT.

So If I did not remember wrongly Nh3 is converted to Nh4 then No2...right then to NO3..so like u said..less Nh4 is taken up hence No2 shoots up....I know PLants take in NH4 rather than No3...right??

What does the Salt do for NO2?? Is it harmful to plants??I can't aerate the water...now right...cos I will cause Co2 to dissipate...from my planted tank..

Anyhow thanks BC Lee// Just out of curiosity..aren't u Forumers working or something?? or are u a student? how come u can reply me during working hours.

Regards
JOachim


My take on what happened. Something might have wiped out the nitrifying bacteria before the whole incident. The N-cycle may have broken down. But your plants are helping to consume the NH3.

When your lights did not turn on, the NH3 level rises causing a NO2 spike.

When NO2 poisoning happened:
- Make BIG water change, 50% or more
- Add some salt to alleviate the NO2 poisoning
- Aerate the water
- Continue water change daily(for more frequently) until NO2 is down to a safe level.


BC

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[bclee]

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On 4/1/2003 3:58:56 PM

Tank is old enough to be fully cycled...since Oct last year
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Still a relatively young tank. Younger tank's N-cycle gets upset more easily compared to a much matured one.

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I think..I inject DIY co2..although the las few days or week..I think the supply has run out...This is not the first time...Need to replenish my sugar and yeast again. Yeah I did add Medicines..for White Spot and Internal Bacteria before..but its weeks ago...and I Think I have already done water change prior to this INCIDENT.
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Many medicine for internal bacteria will wipe the N-bacteria out. If that is 2~3 weeks ago, the residual medication may not let your N-bacteria to recover. Furthermore, it can take up to 4 weeks for your take to cycle, provided you have removed the residual medicine.

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So If I did not remember wrongly Nh3 is converted to Nh4 then No2...right then to NO3..so like u said..less Nh4 is taken up hence No2 shoots up....I know PLants take in NH4 rather than No3...right??
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NH3/NH4 exist together. NH3 in water will ionised into NH4+. Some will stay as NH3 and most ionised into NH4+. Usually, we do not really make a distinct between them.
Plants take up NH3 and NO3.
Bacteria converts NH3/NH4 ---> NO2 ---> NO3.
If plants are able to consume NH3/NH4, there will be less NO2 produced. OTOH, if the NH3/NH4 is not consumed, all will be converted to NO2 and you will have a spike if the bacteria cannot handle NO2 ---> NO3 conversion.

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What does the Salt do for NO2?? Is it harmful to plants??I can't aerate the water...now right...cos I will cause Co2 to dissipate...from my planted tank..
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The idea is to save your fish first!! Your plants won't die in the few days of salt and aeration.

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Anyhow thanks BC Lee// Just out of curiosity..aren't u Forumers working or something?? or are u a student? how come u can reply me during working hours.
----------------

Who say that one cannot reply during working hours!

BC

[geoffrey]

Work? Still looking since 1998!

[Plantbrain]

Rather than going about this from a N or bacterial cycle, try focusing on the plant health. It never does you wrong.

Healthy plants= healthy fish, high O2 levels active bacterial breakdown of other things besides NH4 which in a healthy well run tank, plants get virtually all of it.

Filters mainly serve as backups and for water flow.
The substrate has a great deal of bacteria and surface area and has a fair amount of flow in/out.

Simply doing a large pruning/replanting the tops and removing the bottm portions will greatly reduce the O2 levels by pulling up a large amount of bacteria and detritus from the reductive regions.

Algae like low O2 and will bloom when it's low.

The "cure" is increased plant production.

25mg/l of NO2 is too high, 10mg/l is much better. There should never be any NH4 or NO2 present in your tank.

DIY CO2 is a big issue if you neglect it.That will slow the uptake by plants way down and allow algae to grow.

You can have some current along the surface, just not a lot. That way you'll have some O2 so the fish are not stressed. You can always add more CO2 to make up for the slight loss. Cheaper than buying new fish.

If you focus in on the plants you can have above 10ppm or mg/l of O2 for a good part of the day.

Regards,
Tom Barr
Regards,
Tom Barr

[vinz]

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On 4/1/2003 4:59:27 PM

25mg/l of NO2 is too high, 10mg/l is much better. There should never be any NH4 or NO2 present in your tank.

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From somewhere in the middle of Tom's posting... I think he meant "25mg/l of NO3 is too high..."

[lorba]

Why would salt help?
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According to the book 'Ecology of Planted Aquarium' (should be), salt helps in the denitrification process. Nitrite piosoning occurs with low concentration in freshwater, but remains non-toxic in seawater where its concentration is ten of thhousands time higher.

[joachimsim]

Geoffrey? Looking for a job since 98...a little exaggerating isn;t it.??

I am Communication Engineer looking for a job...in IT or Electronics or Mobile Comm..any recommendations?

Hehe, anyway...thanks to the forumers for helping me out!...Very surprised by the level of activity and RESPONSE TIME here....

HOwever, nobody has told me the replacement for a skimmer and external filter in smaller tank to remove surface oil/scum??


Jo

[bclee]

Yes Tom should be refering to NO3.

I leave the surface film alone. Surface skimmer is to bulky for a 2ft.

BC