Fresh2o
Aquarium Advice Addict
I know someone who kept getting mini cycles in their tank, it turns out they were putting dechlor in the tank water, but refilling through the top filter and the chlorine in the tap was killing off all the bb.
This is a very good tip. After performing a WC, most hob filters require a quick fill for priming because the water usually reverse siphons back into the tank when the tank water level drops. It is tempting to add some of the new water to the top of the filter. I keep a small plastic cup nearby and fill the filter with with tank water PRIOR to refilling the tank.