Join Date: Nov 2007
Location: Calgary, Alberta
Gear pumps are used mainly to create high pressure systems in hydraulics. They don't actually "pump" in the usual definition, they just ram fluid into the system to create the high pressures needed for hydraulics.
As for a piston pump, I'd stay away from it. They require more lubrication than other pumps, and I wouldn't want that leeching into my tank through the piston seals.
In my opinion, the classic peristaltic, or gerotor pump is the best for this application as it is effecient, good with small flow rates, and requires very little lubrication.
I am aware that you can get bio-safe lubes. But they go rancid quickly, and I still wouldn't want it going into my tank.
33G: Eheim 2224, Finally have pressurized Co2 and Reactor