My Nitrates Disappeared

[Dream157]

I have been doing a fish in cycle with bottled bacteria (fritz turbostart 700) for around a month now. I have a 40 gallon freshwater tank with 8 guppies, 3 white skirt tetras and no plants. In order to protect the fish from the ammonia and nitrites I dosed seachem prime every other day. I had no fish deaths. Everything was going as planned. My ammonia and nitrites rose and I got an algae bloom. About a week ago my ammonia finally disappeared, my nitriles started to go down and I had around 5ppm Nitrates. Two days ago my ammonia reached 0ppm, Nitrites 0ppm and Nitrates at 10ppm. So I thought my tank was finally cycled. Yesterday and today I retested everything and ammonia/nitrites were still 0ppm, but all my Nitrates disappeared. It is at 0ppm now. I tripled tested to make sure it wasn't a false reading (API master test kit). What the heck happened?

[Aiken Drum]

Really shake the heck out of bottle #2. Like bang it on the countertop. There should be visible whiteish residue in the drops from the bottle. Maybe squeeze the bottle out of shape to get the residue unstuck from the side of the bottle.

Get a second opinion. Use a different test kit or take a sample to your fish store.

If after all that, and you are confident your testing is accurate, stop worrying about it. Your ammonia and nitrite being zero is more important than nitrate not bring zero. All sorts of things in your aquarium can throw off test results, especially nitrate tests. Its a home test kit, not laboratory testing. Nitrate might just take a while to get to detectable levels, and its entirely possible your previous positive nitrate test results where false positives due to the presence of nitrite.

[Andy Sager]

Double checking with another kit or at a store is always a good idea just to make sure your kit is accurate. Adding to Aiken's comment tho, check the expiration date on the reagents. With the API kit, the nitrate reagents seem to go bad much faster than the other reagents. Even a month or so before the expiration date

[Dream157]

It is a relatively new test kit. The expiration for all bottles isn't until 2027. I banged it on the countertop multiple times before shaking the crap out of it for each test so I don't think that's the issue. I will try buying another nitrate test kit and see what it says. If the Nitrate is truly 0ppm what is my next step? Poor more of the bottled bacteria into the tank or just continue to wait?

[Andy Sager]

Originally Posted by Dream157

It is a relatively new test kit. The expiration for all bottles isn't until 2027. I banged it on the countertop multiple times before shaking the crap out of it for each test so I don't think that's the issue. I will try buying another nitrate test kit and see what it says. If the Nitrate is truly 0ppm what is my next step? Poor more of the bottled bacteria into the tank or just continue to wait?

Do nothing. The dream is 0 nitrates post cycling process. It's just so hard to do when nitrates are the end product of the nitrogen cycle ( meaning that if you have ammonia, you will have nitrates. ) Another question is do you have materials in your filter or used chemicals that may be nitrate absorbers? Things like Poly Filter pads, Purigen, Seachem PRIME, etc. If you used or are using these, they are obviously doing their job.