How many sponge filters to use?

[Jack CO]

I’m planning on setting up a new aquarium in the coming weeks, either a 40 or 55 gallon depending on the size of  stand I can find at a good price. My planned stocking for the aquarium is going to be 3 African butterfly fish, a group of 6 petricola catfish (possibly more in the future) and a rope fish. I want to get the sponge filters to limit the flow because I know the butterfly fish prefer water that has little to no movement and I can easily put something at the surface to stop the ripples caused by the sponge filter. I’m just wondering if 1 large ACO sponge filter will suffice or if I should get multiple. I’ve seen people do it both ways and I’m just wondering what you guys would recommend.
Thanks, 

Jack

[lefty o]

in a 55, i myself would go with 2 mediums.

[redfish]

I'm currently using 1 large in a 55 gal but also have HOB's.  I think I would use 2 mediums if that was all I was using. Having two sponges allows you to alternate cleaning each sponge weekly so you don't disrupt the cycled ecosystem as much.

[Andy's Fish Den]

I use two sponge filters in any tank that is over 24" long in my fish room. I think it helps a lot with flow from one side to the other, in the longer tanks, and would highly recommend using two in a four foot tank. 

[Jackson]

I have a sponge and hob in a 10g  .... 😁