[Chicago]

have been talking on bb about closed loops and just had a thought..my current tank uses eductors on the returns to create more current..think i should continue using them oin the new tank?

[JamesB]

Eductors are really flow restrictions that result in a higher fluid velocity through the restricted area. Usually, a tee joins in at the restriction. The higher velocity results in a lower local pressure, and an additional fluid can be sucked into the main flow stream without directly pumping it in. Eductors are normally used for gradually adding chemicals of some sort into the system. Venturis are a type of eductor in which air is the added "fluid."

The "eductors" (really flow diverters or restrictors) on your returns don't really create more current, they create more velocity with a tighter flow stream. This spreads the turbulence over a larger area and mixes the water in the tank better.

As my first try at your new tank, I'd keep the "eductors" on and judge for yourself as to whether you need them.

HTH, James.

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[Martyn]

interesting
a recent thread on this subject.

http://reefcentral.com/forums/showth...hreadid=157682

Martyn

[Poseidon]

I agree, high school physics class smaller diameter equal high velocity not more volume.

Mike