Explain Rise in Nitrites

[theotheragentm]

My friend had a rise in his nitrites, and only nitrites, which claimed three barbs and some shrimp. I had no explanation as to why this happened as what he told me seemed normal. He was having algae problems so he dosed on the high side of Excel and did a water change afterwards of 25%. Nothing he told me was out of the ordinary in his handling of his tank, except for one thing. He used his bathtub water instead of sink water to refill his tank. He said he treated everything too, so I'm not sure what would cause any problems. Could it be soap?

 

[SparKy697]

Bathtub water? As in from the bathtub faucet? Or from the actual tub?

 

[theotheragentm]

Faucet.

 

[Zagz]

The water should be the same from the bathtub and the sink. Unless of course he has a water softner. That shouldn't cause a rise in nitrite. There usually is a rise in ammonia. He may have just missed the rise in ammonia. Did he add any new livestock to the tank?

 

[theotheragentm]

Nope. Nothing new was added in the tank. It baffles me as well.

 

[tbuh]

Theotheragentm has actually been asking about my tank.

After my first fish died, I did a 25% water change (water only), and the next day I lost another fish and did another change (again water only). I lost a third barb and decided I needed to gravel vac, and changed out about 20%.

I've since added a double dose of cycle (8 caps for my 40 gallon), and everything seems to have levelled off. Now that I'm past the crisis stage of worrying about my fish, I'd like to make sure it doesn't happen agian to future fish!

Water chemistry after the first change was:
pH: 7.2
Ammonia: 0
Nitrate: 5
Nitrite: .25
kH: 7
gH: 10

After the second change, the nitrites went up to .50 (although I may have not been paying attention and it was in fact .50 the first time).

I haven't done another check on nitrites since adding the Cycle, but plan to do so tonight.

Thanks for your help!

 

[Jchillin]

Welcome to AA tbuh.

I assume this is an established "cycled" tank? If that is the case the rise in nitrites may have been caused by the fish deaths. With an established bio-filter, it is very possible that the ammonia spike was missed and the appearance of nitrites was at the end of the episode.

How has your nitrate readings been prior to this episode?

 

[tbuh]

There haven't. This is a relatively new tank, also, though, about 3 weeks old now.

It's a 40g that I populated w/the water from an established 10g and 20g. The 10g was having problems and several fish died in there, so perhaps some of that badness got into this new tank. The 20g was planted and had 2 bags of flourite as substrate, which I combined w/a bag of eco-complete to set this tank up. I moved over the AC 50 that I used on the 20, and have been running it in conjunction w/a new eheim 2236 (rated for 80g). I did stop the HOB filter the day before my fish died, and the two had only been running together for about 2.5 weeks at that point. Could it have been that there wasn't enough bio filtration w/the cannister only being 2.5 weeks old?

I've since restarted the HOB and rinsed out the sponge and bio bag.

Looks like that Cycle worked, Nitrites are back at 0ppm...

Crazy...

 

[Jchillin]

Could it have been that there wasn't enough bio filtration w/the cannister only being 2.5 weeks old?

Bingo! That will always occur with a new filter getting it's legs under it. Glad to hear that the nitrites went down (although I will not attribute it to the use of the "Cycle" product).