Which filter best for 40g breeder?

Looking to pick up a AC70 or AC50 for a 40g breeder. Will a AC70 make fish swirl like a toilet bowl? Or is it just right?

Thanks

Will

Ive had waaaaaaaaaaay more powerful filters in a 40, should be fine.

It is all about filter design i get more current from old penguin filters than the new emperor 400
because of the part that the water falls from is extended on the emp.my 78 cube looks like its barely moving and my planted has the top flowing like a river.Are the fish you are getting or have gonna like fast water i know my minnows like the faster the better.good luck

My take on HOB filters is pretty much get a filter rated for double your tank size and you will have less problems. I use a Penguin 350 on my 29g and it is just right. It is "rated" for up to something like 70g. The design works great for surface agitation with very little current. The only downfall to me is the whole cartridge thing. That is one thing I like about the Aquaclear is the adaptability of media. If I was looking at an AQ for the 40 I personally would be looking to use at least the 70. But I always over filter.

Sponge filters FTW!

Granted, I don't keep large fish... but "they" make pretty big sponge filters. When I keep fish that prefer current I add a powerhead and call it good.