I take it you mean a submersible aquarium pump.
I just bought a middle of the range size pump that had adjustable flowrate. I'll dig out the brand and name tonight.
The main thing to keep in mind is the height you need to pump. The higher you need to go the bigger the pump you need.
The flow rate doesn't need to be all that fast however.
We are talking about using a pump for chilling fonts, so I bought one that had only an out connection. The inlet is bascially just a grill.
There are some pics in the gallery (in the freezer conversion section), but can take more tonight if needed.
The tube for the out fitted the copper cooling coil that goes through my font perfectly. From memory the tube is 8mm.
I take it you mean a submersible aquarium pump.
I just bought a middle of the range size pump that had adjustable flowrate. I'll dig out the brand and name tonight.