[GMGQ]

I have my return split on a Locline Y, with a hydor flo on each end. Definitely better than without.

However they do drastically reduce the flow. It's basically a propeller and a gear inside, which the water has to flow through, and those obstacles sorta slow down the water flow.

That's the trade-off for more varied flow. Just dont count on these as your main source of flowage and you'll be fine. (i.e. my main source is a closed loop system with an OM squirt and a couple of OM revs).

p.s. I got them from Big Al's online. They're actually cheaper from their online site, than in store. Franchises, go figure.