which pump should I buy?
 

12 VDC CENTRIFUGAL PUMP or the Mag-Drive Supreme 3 350 GPH Water Pump

Specs are,
12 VDC CENTRIFUGAL PUMP:
12 volts DC
2.2 amps
Duty continuous
7 GPM @ 1.5 PSI
Ports 3/4" hose barb
Temp range 40 - 170 deg F
Size 6" x 3" x 2 1/4"
Shpg 2 lbs

Mag-Drive Supreme 3 350 GPH Water Pump:
Flow Rate: 350 GPH
Watts: 35
Pump Size (L x W x H): 5.0" x 3.8" x 4.2"
Outlet Size / Inlet Size: 1/2" MPT / 1/2" FPT

I dont think actual heat generated from the pump will be a problem, because I have a sepp. case that is goign to hold the pump, radiator, and resivor. What do you guys think? there both aroudn the same price. I do however kinda like the first one a lil better. Your thoughs are appreciated!

My Mag 3 is very quiet and has run ever since I plugged it in, a few months ago. The flow rate as far as I can tell is all that I need for a single computer. I'd buy another one if i was building another setup. I dont know if the other pump is better or not.

I agree. Mag 3 is a well known pump of good price and quality. Be safe, go for the Mag 3.

is that the johnson discussed here? - if so it may not have a long lifespan iirc...
http://forums.procooling.com/vbb/showthread.php?t=6650

I'm pretty sure that is the pump in question. It looks like a solidly performing pump, but nobody is sure how long it will last. It has a brushed motor, so once the brushes wear down, the pump will fail. The Johnson supposedly gets very hot when it runs.

The mag 3 on the other hand, is designed to last more or less indefinitely. It runs cool, has no [brushes], and uses a sealed magnetic drive. I can't say if the Johnson is mag-drive or sealed shaft, so this would be worth looking into.

I too would say go for the danner unless you really need the massive pumping power for some reason and can take the risks.

edit: meant to say brushes rather than magnets

In addition, if the Mag3 ever needs servicing you can replace the impeller assy as a unit for 9 dollars. I have two extras on hand if I ever need them.

Krazy you said it has no magnets, I guess you meant to say it has no BRUSHES. It does have a magnet in it.

There is no shielding around it though, something to be aware of if the pump will be close to a CRT type monitor. It will cause the screen to flicker. Since my PC is on the floor about 3 feet from the screen, its not a problem for me. As far as interfering with the PC itself or disks, I tried leaning a floppy against the pump and cycling it on/off several times, and it lost no files.

I didnt bother with a relay or anything for it, I just plugged it in. Just guessing, it ought to run continually problem free for a few years at least.

Here's a good supplier for this pump...

http://www.reefgeek.com/

Another vote for the mag 3 :D

I am a very satisfied owner. Reefgeek is very good about replacement parts too, I had to replace a impellor housing for the mag three because I was stupid and wrenched in a brass fitting WAY too tight and busted the plastic. I think the replacement was like 3 bucks + shipping. Reefgeek is a good website for that stuff.

You should get and examine the pump P-Q curves for each pump, maximum head pressure is more important than maximum flow all else being equal. If a pump doesn't have a P-Q curve available, I wouldn't buy it. Note also that the maximum flow will be at 0 head pressure, and the max head will have 0 flow, so you will never have both at the same time. The P-Q curve defines how much flow you should expect at a given pressure. Since a WC system has a fairly high resistance, a high head - low flow pump will give more flow in practice than a low head - high flow pump.

It also helps to translate all the measurments into the same units - ie either GPM or GPH, (or LPM / LPH for the metric folks) Head pressure is normally measured in either feet or meters of water. There is about .445 PSI per foot of water, so the 12VDC pump is approx 420 GPM at 3.2 feet, which is a very low head pressure. I forget the Danner flow exactly, but the P-Q curve is here on this site somewhere, and as I recall the Danner has a max head of around 8-10 feet, which makes it a better pump even though it has a lower 0 head volume.

FWIW, I ended up getting an Iwaki, but if I hadn't, the Danner was on my short list of candidates as possible pumps, so you could count me as another Danner vote, sort of...

Gooserider

thanks guys. Im deff goign with the mag 3 :)