I have been keeping fish for years, I have two very established tanks. I have a 20 gallon tank (107 Fluval and a Sponge filter), I have a 40 Gallon tank (306 Fluval and Sponge filter).
I recently purchased a 5.5 Gallon Tank, added pool sand as a substrate, added Java Moss (From my 40 gallon), added Water Sprite from my 10 Gallon, and added my 20 Gallon Sponge filter into the tank. (I bought a new Sponge filter and put it in my 20 Gallon Tank.)
I dosed the 5 gallon tank with Fritz Zyme 7. (This was over two weeks ago fyi). To make sure I did not kill I put 8 drops of DrTim’s Aquatics Ammonium Chloride Solution into the tank. Not a whole bunch but just a little to get a Ammonia reading from the tank.
The next day, The Ammonia was 0ppm. The Nitrite was 0.25ppm and Nitrate was 5ppm. (This was two weeks ago).
SINCE THEN, I've been testing the tank every morning, and I get the same reading every day. 0 Ammonia, 0.25ppm Nitrite and 5ppm Nitrate.
This has been two weeks, I do not feed the tank, I do not dose anything into it. I did not do any water changes either.
A bit impatient, last night I did a 50% water change and I got 0 Ammonia, 0 Nitrite and a slight tint of orange on Nitrate.
10 hours later, this morning, I tested the water ... Ammonia is at 0ppm, Nitrite at 0.25ppm and Nitrate was around (my guess) slight orange 2ppm.
I am puzzled, I have not put any food in the tank, I have not put anything live in the tank. For the life of me, I do not understand why the tank has 0.25 nitrite. The tank has Java Moss, Water Sprite and Java Fern in the tank. Water is clear and the back glass has a slight tint of green algae growing on it. Tank has a Heater (set at 75 degrees), Hygger full spectrum light, Aquarrium Coop Medium Sponge Filter.
Any one have any suggestions? What am I missing (I'm not feeding the tank and the only time I added ammonia to the tank was the first day, none since.)
