Submersible pump--aquarium?

[zahc]

I have a 55 gallon aquarium. I want to pump water from it, about 40 feet over to my computer. So I need a submersible pump, that preferably runs on 120v, and is very quiet. Should I just look at an aquarium store or is there a cheaper option you can think of?

[Sindawe]

I just have to ask. Why are you doing this?  Do you have some cool water analysis equipment and software that runs on the PC?  Are you perhaps thinking of use the aquarium water for cooling the components of the PC?

Try this search: http://www.google.com/search?hl=en&safe=off&q=submersible+aquarium+water+pumps&btnG=Search

I may be odd, but for moving liquids around I really like peristaltic pumps: http://www.google.com/search?hl=en&safe=off&q=peristaltic+pump&btnG=Search

[zahc]

I was going to use it to cool the PC. I figure, that way I won't need fans at all. And the pump will be silent since it's submersed and across the room.

[Gewehr98]

Running fish tank water through computer CPU and video card cooling blocks ain't the best thing for the parts.  Most computer water-cooling systems actually run distilled water with an additive, and the most recent ones I've played with run 50/50 antifreeze/distilled water for best heat transfer. 

I had a Koolance system for a while.  It did a good job cooling down my overclocked Athlon MP system, but it was neither quieter nor cooler than current air-cooled systems.  The technique of water-cooling computers has graduated from the kit-basher who drills holes in a block of aluminum or copper, buys an aquarium or fountain pump, and uses Chevette heater cores as the radiator, to complete systems that are ready to go off-the-shelf.  It's taken the mystique and magic out of the whole process, and has begun a decline into obscurity. 

Here in 2007, with the improved air-cooling systems, fewer overclocked chipsets, and processors generating less heat, one has a hard time getting a water-cooled computer to really run that much cooler than its air-cooled counterpart. 

The concept is neat, I know of one guy who actually used his ground water heat pump and a water/water heat exchanger to basically cool his computer to ground water temps.  But ground water never entered his computer, just like fish tank water shouldn't run through yours.  (Unless you really want an algae bloom in the cooling circuit, organic sludge buildup, etc)

The rise and fall of PC water cooling systems:

http://www.procooling.com/index.php?func=articles&disp=148

[mfree]

If you're dead set on using the aquarium for a PC heat sink (or conversely, heating the aquarium with your PC) I'd recommend using a heat exchanger and avoiding gettin aquarium water in your cooling system.

As for moving the water itself, I'd definitely use hard line over that kind of span, using like metals to what's preexisting if it's all one metal (i.e. copper cooling block and nothing else gets copper pipe... if it's copper/steel mix with an antielectrolytic additive then anything goes and I'd probably use stainless brake or fuel line).