Aquaclear (Hagen) 50 powerhead

[gohy898]

Hello All. New to this forum. I am from Melbourne, Australia.

Just set up my reverse flow UGF with the Aquaclear 50 powerhead. It seems to be working but do you need to put the air hose supplied through the Venturi unit if doing reverse flow?

Also, in reverse flow, do you really need a sponge to cover up the intake valve?

I will be keeping ranchus and my tank is 21 gallons or 80 liters.

Thanks! Looking forward to your input.
Cheers