Thanks. I never even has the sponge in there. I have the Intank media shelf in chamber 1 with floss on top, carbon in the middle, and Fluval bio media in the bottom. Just the heater in chamber 2 right now. I have a powerhead for flow too.I've had my Evo running since 2018 with the standard pump. I've not once felt a need to upgrade it, however I did remove the internal sponge from it which got nasty too quickly. Obviously there's a risk in running it without the sponge but I have floss in the prior chamber. I did add a powerhead for more flow in general, but obviously that does not increase flow through the filter which might be some people's motivation to upgrade.
I agree with the flow through the filter. I think if managing nutrients is an issue, I’ll consider a pump upgrade. But not now.