Nitrite false positive - possible?

[agiacosa]

I'm sitting on my third week of high nitrites during initial cycle. I've done two 50% water changes and they have barely come down. Using API test strips.

Is it possible for a test kit to give a false positive?

Thanks


Regards,

Art

 

[disc1]

Ditch the strips and get a real test.

Nitrite can fool a nitrate test. Have you measured nitrite?

 

[gbru316]

On the nano I just started, It took 5 weeks for nitrite to drop and 6 weeks to reduce to 0.


That being said, I generally trust titration kits more than test strips.

 

[disc1]

Ditch the strips and get a real test.

Nitrite can fool a nitrate test. Have you measured nitrite?

Sorry. I think I misread your post and thought you said nitrates.

It is normal for nitrite to be high in a tank that is still getting the cycle going. Best to wait it out. And get some real tests while you wait.

 

[Motish]

Hi,
You shouldn't replace water while cycling either...

 

[gbru316]

Hi,
You shouldn't replace water while cycling either...

false. Depends on situation. If you want to preserve any livestock or hitchhikers, you most definitely should.

If it's an empty tank, it doesn't matter.

 

[agiacosa]

Thanks.

I understood that if nitrites went over 5 ppm you could stall the cycle. A water change would be required to bring them below. I assume the bacteria is not free floating and would not be removed with a water change.

Thoughts?

 

[gbru316]

Bacteria colonizes surfaces in the tank. Changing water will not result in a removal of bacteria, merely a removal of the byproducts of said bacteria.

 

[billsreef]

I understood that if nitrites went over 5 ppm you could stall the cycle.

You've been given bad info with that. High nitrites won't stall the cycle.

 

[agiacosa]

Bill,

I got it from Dr. Tim. Please see his troubleshooting section here: http://www.drtimsaquatics.com/resources/fishless-cycling/how-to-start

 

[Mr. Bill]

A false reading is not only possible, but sounds probable here as water changes should've lowered the levels. Test kits/reagents do go bad and need replaced periodically.

 

[billsreef]

You need to read it a bit closer The 5mg/l figure is in reference to his bacteria blend. While it's true high ammonia and nitrite levels can inhibit (aka slow down) the nitrifying bacteria, it's a bit more complex than that. High ammonia levels inhibit the bacteria that convert nitrite to nitrate, but once the bacteria that convert ammonia to nitrite really kick in and drop the ammonia, the nitrite converting bacteria will kick into action and start converting that nitrite to nitrate...and thus complete the cycle. A little patience and those high levels will come down as the cycle does indeed complete itself despite them. I've dosed systems pretty high, and never had a cycle not complete as expected The one place he does actually talk about stalling the cycle is in reference to low pH. I've always maintained normal pH during cycles, so can't say from experience if that actually happens or not.

 

[agiacosa]

I'll be getting a new test kit tomorrow.

Bill, I think I get it. How long have your nitrite phases been?




Regards,

Art

 

[billsreef]

Nitrite phases can last a couple of weeks, depending on high they spiked...which directly correlates to how high the ammonia previously spiked. Typically I find a cycle in your classic biofilter type fish tank or aquaculture set up will take a solid 6 to 8 weeks. Reef tank scenario using cured live rock and live sand can take half that time.