Fluval pre-filter affect GPH output?

[isabellidancer]

Hi. I have a Fluval Flex 9 gal for my betta fish. It's currently being cycled, and I have a pre-filter sponge on the output pump nozzle to reduce the flow of water. This has significantly reduced the flow, which is great, but does it also reduce the pump output? The fluval site says the flex 9gal should have an output of 61 GPH. I plan on giving my betta a few tank mates, but I want to make sure my filter is turning over the water enough before I add. Thanks!

 

[Flyfisha]

As I understand it . Fluval is like most manufacturers and measure their filters without any media at all.

So their rating is already not a true rating anyway.
Don’t worry about it.

I should add some of the Fluval pre filters I have seen are very fine sponge. They need cleaning almost every week.
You may find a course sponge lasts longer between cleaning?