I've had to change the filter from a 5-gallon to a 10-gallon a few days ago because my 5 gallon was leaking. I'm relieved I got a bigger tank for my mollies since a 5-gallon was way too small for them but now I'm worried because my Nitrate and Nitrite levels are high and I just did a 35% water change. I put the filter that came with the 5-gallon into the 10-gallon tank and was wondering if this was the cause of the nitrate and nitrite levels to increase?
Can you add another filter to the one that is already there? You can run both of them at the same time. You can never overfilter. This way your new tank will have the benifit of an already established filter and the added benefit of a new filter to give more filteratin and oxygen for your fish.
I'm planning on getting a more powerful filter once I have enough money which should be in a few weeks and keep the other on for even more filtration. Thanks for the help!