It is best to run the water through our Premium or Classic filter pad before water passes through our polishing pad. If water flows well through your filter using our premium or classic filter pad by itself then you will need to slow the flow rate down. Hopefully your water pump has a valve to slow the flow so water will pass through the polishing pad.
When you are not polishing your water you can turn the pump flow back up if you like. Polishing pads have such a tight weave they can not handle large volumes of water at once. Since most hobbyists use powerheads to circulate the aquarium water you do not need a high flow rate going through your wet dry filter. Depending on your system actually slowing the water down can make your mechanical, biological and chemical filtration move effective. Please let us know if you have any more questions.