This was very good info for me a new Betta owner.
I set up my 2 2.5 gallon tanks last Thursday on Friday after work I bought 2 Bettas at Petco. My tanks each have a filter Tetra Whisper 3i, each have a slim heater some decor and a masamo moss ball. I have two larger cycled aquariums so I used 2 cups of small smooth river rocks from my 18 gallon Community tank. I have the API master test kits and on Sunday and again today my amonia was 1, I did 50% water changes on Sun and today. Is this normal to acumulate this much Amonia in 2 days?