Nitrite Spike


Its been almost a month of having my fish as follows in my 65 gallon tank:

1 - rubberlip pleco
2 - blood parrots
6 - german blue rams

For 2-3 weeks the tank was 0-0-10
Then ammonia and nitrite started spiking around the 4th week out of nowhere.

I was doing weekly gravel vacuuming during itch treatment and about 50% water change. I'm not sure if the gravel vacuuming killed my bb? I also have a fluval canister filter.

1st picture is 1 week ago when ammonia and nitrite spiked. I did a water change and threw in a nitra-zorb in the filter. 2 days latter my parameters were 0-0-0. I checked today 6 days after the water change and to my surprise ammonia was fine but nitrites were even higher than last week! I attached the picture.

From left to right in each picture is ammonia, nitrite, and nitrates. The one with the darker purple nitrite reading was todays parameters.

What is causing this nitrite spike? The fish are not acting different and seem fine so was surprised to see such bad levels.


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Were your test vials possibly contaminated? I've done tests where I got a surprising result, and have then washed out the vial with RO water, and then tank water giving it a good shake, redone the test only to find it normal...



I normally wash the tubes thoroughly with a brush so doubt it was contamination. I did end up doing a 80% water change with no gravel vacuuming so can't retest.


what ich treatment did you use?

perhaps the gravel vac stirred up a bunch of poo and caused a minI cycle? do you gravel vac every week?


I had the temperature at 86 and used paraguard for 2 weeks. About 15-20 hours after the water change from last night the nitrites were same level as yesterday again! I immediately did another water change this time closer to 85-90% water change. I tested the levels after the water change and was about .25ppm. I was doing a gravel vac weekly due to the itch treatment before now.

Do I need to do large water changes within hours of changing it? Its a 65 gallon tank so its quite a bit of water I'm using. Or is it better to just dose prime daily and how long until I do a water change? I'm not gravel vacuuming right now to not kill any bb.


Can you possibly try to test your water with another kit or test strips ( although usually not very accurate )? Or maybe bring a sample of your water to your LFS to seewhat their reading come up as?.. With nitrites like that you would think your fish would be acting quite abnormal. Also check the expiration date on your test kit if possible.


I can use a clean container and re-test. I tested my tap water and its 0ppm. My tap water does have a tad bit of ammonia not sure if that's why under 24 hours nitrates would be so high as the ammonia from the water change is being eaten up? But even the month after cycling I never got any nitrite readings.


Last night after the water change nitrite was 0 ppm. This morning I checked again and nitrites were really high! Do I do a water change again or add prime?

The tube on the left was last night and the right side this morning.


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