Odd nitrite level read.

[By_a_coo]

Hello everybody.

I fishless cycled my FW tank four months ago, after one month cycled I started to raise the salinity by .001/week. Since I fluctuate the salinity just a little bit... between 1.003-1.005. At that point, when I read the nitrite level it used to show 0.1-0.2 mg/L. In the course of time, I don't know how, but one day I checked the parameters and the SG was almost zero and the same for nitrite.

The test kitis for both FW/SW and it is not expired. To test FW you have to add 2 drops of each reagent, for SW you have to add just one drop of each reagent. I don't know which method I should use (I tested both method). Now the SG is 1.005, no ammonia, nitrate < 0.5 mg/L and nitrite is between 0.1-02 mg/L. I always do WCs 80%/weekly.

Then I can conclude that I read some nitrite when my tank is BW and nitrite shows zero when the tank is FW. Why? I really don't know what's happening and how to fix it! Does anybody have any clue?

Thank you in advance!

[Pufferpunk]

I'd try another test kit. The one I have (API) uses the same test for both.

[By_a_coo]

Does your test kit use the same method to test FW and SW?

If I don't find a test kit for both type of water, should I buy for FW or SW (my SG 1.003-1.005)?

[Dadof4]

Does your test kit use the same method to test FW and SW?

If I don't find a test kit for both type of water, should I buy for FW or SW (my SG 1.003-1.005)?

Make sure you shake the bottles real good for the nitrite and nitrate. It can make a difference.

[By_a_coo]

Well, I tested the water used to make the WC and nitrite was zero. Then I tested the tap water and its nitrite level was zero too... so I tested the water from the tank and it shows 0,25 mg/L. There's something going wrong in my biological filtration and I don't know what it is. The puffers are looking active and acting normal. I feed them every other day, so the bacteria should do their job and that isn't happening.

If it is a mini cycle, shouldn't the nitrite get low after a couple of weeks? Isn't the SG interfering on bacteria that process the nitrite?

I really trying to realize what's going on, but I'm not finding answers to the problem, even doing research on the subject. That's why I'm asking your help.