This will lead to an increase in nitrates and ammonium compounds. As long as the pH level is below 7.0, the ammonium is not particularly dangerous and does not convert to the poisonous ammonia. Do not overfeed. Keep to ration of maximum 5 minutes feeding frenzy , 2-3 times a day. Avoid cleaning filter media under tap - use the same aquarium water as not to remove too much bacteria.
Tap water has chlorine that kills bacteria, good or bad.
Do not clean all your filters in the same tank at once, do it on alternate weeks so that the remaining bacteria in the tank or filter is able to cope. Performing partial water change can effectively remove ammonium or ammonia in tank. Ensure that the pH level of the new water is at 7.0 or lower. Monitor the nitrates level, any alarming increase should warrant immediate partial water change. I would like to advise new hobbyist to follow some simple recommendations mentioned above , at least for starters when you have acquired your new tank.