Originally Posted by jackster911
i have the 2.5 starter kit so it has a nice filter. can i just do weekly 25 percent changes thats what i saw alot online
If your tank is NOT cycled and you're not going to cycle it, you need 2 weekly water changes- 1 50% change and 1 100% water change.
Without cycling the ammonia will not go any where and therefore 100% changes are needed to rid of excess ammonia.
If you're currently cycling it, you will want to do partial water changes based on your ammonia/nitrite/nitrate levels. If you're cycling, never rinse filter cartridge in tap water or replace it- swish in used tank water to get any guck off. The filter cartridge WILL look brown and gross, but that is because beneficial bacteria are there. BB process ammonia into nitrite into nitrate. Washing or replacing the cartridge will kill them.
You can learn how to fish in cycle here http://www.bettafish.com/showthread.php?t=107771
But I'd reccomend a liquid test kit to measure parameters.