The reason I was asking is because the lady at petsmart this morning told me to try and turn off my filter and see if that helped (along with changing the water conditioner) and so far it has. I am so glad to know that you don't use filters!!
I don't use filters on any of my tanks. But, if you don't use a filter you'll have to do water changes a lot more often. For your 2.5G it should be cleaned twice a week 100% if you don't have a filter. I don't know anything about them or cycling. You could make a thread about it and the people who know everything about filters can answer your questions. Sorry I can't help!