D,
I have been using an assortment of Hyperflows for several years now - The power and flow from these pumps is really astounding.
For my Surge Tan which is located on a second story balcony I use a HF32. And it fills 33g about every 90 seconds at about 14' of head.
The only issue I have found with the Hyperflow is that it creates such pressure and volume by using a unidirectional impeller.
When the pump turns on, if the impeller spins the wrong direction, centrifugal force swings out a little stub to stop the impeller so it spins the correct direction.
However, the little tab sometimes gets stuck inward, so the pump will chatter, or run at what appears to be 1/2 speed. So you might have to plug and unplug it a couple of times to get it to spin the correct direction - Of course if you keep the pump clean and maintained this probably won't happen.
All the Hyperflows have a thermal circuit inside. So if they get jammed, or if you break an impeller shaft, when the pump gets hot, it shuts off. So there are no melt down issues.
They use a stainless shaft with ceramic bearings, The impellar also has ceramic bearings, -- They stainless wears better than stainless to stainless.
As for noise, the pumps are pretty darn silent.
Like I said I have a bunch of them - I really like the Hyperflow 8 - That is a small pump which moves a ton of water with min power consumption.
I use HF 8's for upflows in my frag tanks, I use a HF 12 for my reverse fluidized Calc Reactor, and I use a HF 32 for my surge tank.
All pumps have been in service for over 18 months.
Dave B
