10 Gallon tank, used to be my bare QT tank. I had a Platy and a Rasbora for about a week in the tank, them moved them to another tank. Didn't change the water afterward, left the filter running for 3 months with no fishes. The tank as far as I knew was not cycled.
Bought a 30 gallon tank brand new with new filter and decided to do a fishless cycle with both 30 gallon and 10 gallon tank on the same day.
Bought new substrate for both (Carbisea Instant Sand) and added Ace Ammonia to get 4 ppm on both tank.
3 days later, I check the ammonia on both tanks using API freshwater tube test.
10 gallon tank I read 0 ppm ammonia and 4 ppm nitrite.
30 gallon tank I read 5 ppm ammonia and 0 ppm nitrite.
I add another dose of ammonia to the 10 gallon tank to get 4 ppm of ammonia.
I add some media from another tank to the 30 gallon.
On the 4th day (today), I do another test.
10 gallon tank I read 0 ppm ammonia, 5 ppm nitrite, 20 ppm nitrate.
30 gallon tank I read 2 ppm ammonia, 2 ppm nitrite, 0 ppm nitrate.
Why is the 10 gallon tank cycling so much quicker?
Is it possible that leaving the fish waste for 3 months and leaving the filter on the cause why it is cycling faster?
There was only a little bit of fish waste as it was only 2 fishes, and it was only a day's worth of waste from those two fishes.