Mag Drive Return Pump - Submerged or External?

[MeuserReef]

Im currently using a MAG 12 as my return/chiller feed pump and have it submerged in my sump. I plan on using this same pump on my new 120, but would like to keep heat to a minimum (my tank is upstairs where all the heat likes to migrate)

Will running a MAG Drive pump externally reduce the heat that it introduces into the system's water? If so, then I will run it external to my sump. If the heat introduction is going to be roughtly the same whether submerged or external, then I will just keep it sumberged. One less bulkhead = one less potential leak :D

[sjm817]

It will be roughly the same. It is cooled by water passages inside the pump.

[JaredWaites]

I think it makes a difference IMO.

I've noticed a significant heat increase while running them for powerheads...but when they are used externally for other purposes, I've never had any heat issues. I don't think they really add that much heat to your water, but you add up all of the other pumps and you have yourself a problem ;)

[MeuserReef]

<a href=showthread.php?s=&postid=12164089#post12164089 target=_blank>Originally posted</a> by sjm817
It will be roughly the same. It is cooled by water passages inside the pump.

So this would mean that the majority of the heat from the windings of the pump would still be carried away by water, regardless of how its plumbed.

<a href=showthread.php?s=&postid=12164188#post12164188 target=_blank>Originally posted</a> by JaredWaites
I think it makes a difference IMO.

I've noticed a significant heat increase while running them for powerheads...but when they are used externally for other purposes, I've never had any heat issues. I don't think they really add that much heat to your water, but you add up all of the other pumps and you have yourself a problem ;)

I guess that if any heat travels into the air (when plumbed externally) it cant get into the water. I wonder if there is any hard data out there concerning these pumps. Probably not eh?

[Spuds725]

no hard data but a plethora of opinions ;)

IMO.. it will add a little bit more heat when run submerged-- depending on your system size, design and heat losses it may or may not affect your temperature

I'm will be running mine submerged-- but my system volume is over 220 gallons with a basement sump (pretty cool room)

[sjm817]

Someone ran a test with a Mag9 not too long ago. The results were it added ~ the same amount of heat either way. Its a water cooled pump cooled by the water passing through it. It has nothing on the case that actively radiates heat to the air. No cooling fins, no fan. There may be a slight difference, but nothing that would be noticeable. A similar example are the Velocity external pumps. Even though they are an external only pump, they transfer a lot of heat to the water because they are water cooled, not air cooled like most externals.

[itstheantitang]

I'm pretty sure Danner (mag drive manufacturer) only recommends external use of mags on freshwater setups.

[lark]

I can't tell you the answer, but I can give you one more little piece of anecdotal evidence. When I removed a mag 3 feeding a closed loop (external) in my 90g, the average temp dropped about 2 degrees. Not sure if it would have been different submerged, but external does definitely add some heat.

[MeuserReef]

Thanks everyone for the feedback. Since the motor is water cooled, I suppose I will just keep it as a submerged pump. This will prevent me ffrom having to drill my sump!

[ShipOFools]

Im trying to find it but I think I read somwhere danner does NOT reccomend external setup for their pumps

[kevin95695]

I run a MAG9.5 to power the venturi/vortex in my DIY skimmer. It runs external. I put my hand on the pump body. It feels hot. That heat would otherwise be heating water if the pump were submerged. Personal observation, that's all.

[Roy G. Biv]

<a href=showthread.php?s=&postid=12163563#post12163563 target=_blank>Originally posted</a> by MeuserReef
Im currently using a MAG 12 as my return/chiller feed pump and have it submerged in my sump. I plan on using this same pump on my new 120,

Is a Mag12 strong enough? The headloss calculator says this for 12 vertical no elbows.

Total losses are 12.78 feet of head pressure, or 5.52 PSI. with a flow rate of 287 GPH.

[strayvoltage]

I can't find it right now, but I have also read it advertised for the mag pumps for submerged use only.

[kcress]

Remember that all the power a pump consumes ends up heating the water. (Conservation of energy.) These little pumps aren't overly efficient so about 15~20% of their power is just directly turned into heat. If the pump can run externally and it gets very warm then that IS heat that would not be directly conducted into the water.

How much difference? I'd say if the body gets uncomfortably warm or "really" warm. External mount it! If it gets a little warm or slightly over the water temp then don't bother as the design is effectively directing most the heat into to water anyway. You might want a different pump that doesn't conduct the heat to the water.

[Siffy]

http://www.reefcentral.com/forums/showthread.php?s=&threadid=1164595

"Will running a MAG Drive pump externally reduce the heat that it introduces into the system's water?"

No. And actually from 8ball's test data it appears to add more heat if run externally. As the pump runs hotter, it runs less efficiently, draws more power, and transfers even more to the water overall.

[sjm817]

<a href=showthread.php?s=&postid=12170809#post12170809 target=_blank>Originally posted</a> by Siffy
http://www.reefcentral.com/forums/showthread.php?s=&threadid=1164595

"Will running a MAG Drive pump externally reduce the heat that it introduces into the system's water?"

No. And actually from 8ball's test data it appears to add more heat if run externally. As the pump runs hotter, it runs less efficiently, draws more power, and transfers even more to the water overall.
Thanks, I think that is the test I remember seeing, but I thought it was a Mag9.5.

[kevin95695]

Siffy's got some points to ponder. Hmmm.

[civicunrest]

My average system temp on my 120G went up about 2 degrees running a Mag 24 submerged versus external. I had to replumb it when I built my new stand. Then again, a Mag 24 is a lot more pump than a Mag 12. :-)