I've never understood this...Why do people restrict their return flow?

[garbermatt]

Just plumbing my new 240g build and thinking I'm just going to use a 1" black PVC with a check valve to get maximum flow from my return pump. But it seems the default for a return is always these super restrictive nozzle things but I always shudder when I see them because all i can think of is that they must totally stifle flow. Am I missing something? Should I consider having like 4 of these nozzles instead of my one big PVC pipe?

 

[ying yang]

Maybe reason is because less flow through sump more desirable so water got chance to go in skimmer/ reactors etc as faster water goes through pump and nozzles etc,providing overflow can handle it then more water goes down overflow and through sump ?

 

[blaxsun]

For those of us with very, very fine substrate, it's partially to avoid the "snow globe" effect. I don't think the outlets restrict the flow as much as you think, though.

 

[TheDragonsReef]

Yeah you should be running north of 2000gph in a 240 and just 2 of those wont be enough

 

[jdiefenbaugh]

It's a matter of velocity vs. volume. Think of using a garden hose when you put your thumb over it, versus just letting it run out. This is a gross over simplification of fluid dynamics, but in essence is what is going on.

 

[Smite]

Look into flow eductors. Those are meant for smaller tanks to fan out the flow.

 

[Rmckoy]

I can’t run my return pump at 100%
It a a 15000L jeabo .

I only have 1 over flow drain and if I turn the pump up the drain can’t keep up

 

[garbermatt]

OK, so sounds like multiple reasons for different types of return plumbing. So duckbill is good for some tank setups and not others.