The water flow rate of Filter A is such that it can fill a cup of water in one second, while Filter B requires three seconds to fill the same cup. Under the condition that the filter media are identical, I would definitely choose Filter A, which can fill a cup of water in one second. This is because A’s water flow rate is three times that of B, meaning that while B circulates the water in one tank once, A has already circulated the water three times. This is the advantage of a higher flow rate.
Is a Higher Flow Rate Always Better?
Of course not, the first thing to consider when choosing a filter is what kind of fish you are keeping, followed by the size of the tank. Generally speaking, the filtration flow rate should be five to ten times the water volume. If it reaches ten times, that is very ideal.
For example: The dimensions of my tank are 60x35x30 centimeters, and the calculated water volume is (60x35x30)/1000, approximately 63 liters. Therefore, ten times the flow rate would be 630 liters per hour. The flow rate parameter of the filter I chose is 650L/h, just over ten times, so my filter fully meets the needs of my tank, and there are basically no problems.
Original article by KPTer, if reproduced, please cite the source: https://www.kaipet.com/en/higher-water-flow-aquarium-filters-key-factors-filter-selection
