I have 2 2.5 gallons tanks. Each tank has A betta, java moss, shelter, substrate and river stone, plastic plants and a shelter. And each has a hydor mini heater. With all this stuff in it, each tank really only holds about 1.5 gallons. They have been running for about a week. I'm not trying to cycling them. I understand they are too small to be effectively cycled.
Here is the main difference: One has a Tom mini internal filter; the other is not filtered. Mostly because I could only find 1 mini filter so far.
I treat and change the water on the two tanks the same way. Why is the ammonia reading in the filtered tank consistenly higher than the unfiltered tank?