filter change after 2-1/2 weeks

Question
Hi,
helping my mom with her new 10 gallon freshwater tank.  She bought it primarily was purchased to add African Dwarf Frogs.  We initially put in the tank 3 ghost fish to "create good bacteria" according the fish store.  Then 1 week later we added 4 of the frogs.  I decided then to add a real plant vs all the plastic ones she had.  Bad move.  It came apart during the night.  All the plant leaves were floating around the tank and the thing holding them together exploded with perlite or some other kind of medium.  When I got there all this perlite was floating around the top of the tank and the filter intake was clogged with the stuff. While cleaning this out, I checked the filter and it looked horrible (I don't know what it should look like) so not know any better I changed the filter.  Everyone in the tank is doing ok, but the nitrite levels are going up.  I am changing 25% of the water today, note that approximately 1 1/2 to 2 inches have evaporated.  What advise can you give me at this point?  How do I compensate for changing the filter and possibly messing up the good bacteria ratio?

Answer
Melody,
Unfortunately, most large pet store chain no nothing about the fish they sell. When you set up a new tank, it goes through a cycle process. This process takes up to 6 weeks and sometimes longer. During this time there should be no fish in the tank. During the first week or so of the cycle process, you will see the water get cloudy. This is normal. Your nitrite levels are going up because of the cycle process. Test your water every day and do a water change depending on the levels but never more than 40%. If things start to get worse let me know.