Mag-drive pumps not for external use?

[Anonymous]

I just got a Mag-drive pump to use in a closed loop, and notice the Marine-Depot site says not recommended for external use? Anyone know why?

 

[Anonymous]

Weird, there is another post on the same subject...

 

[Alf3482]

I have a MAG 12 and a MAG 7 That I use externaly. Works fine :?

 

[fishfarmer]

I've read the same thing, but the instructions that come with the pumps say they can be used for either.

 

[playfair]

Personally, I use a Mag18 externally for return, but I wouldn't use a Mag pump for a closed loop... They are decent pumps, but not of the highest construction. It is not uncommon to have the fittings on the pump housing crack, which in the case of a closed loop, you loose most of your tank water!

 

[O P Ing]

...crack, which in the case of a closed loop, you loose most of your tank water!

hi.
For close loop, it is usually have the pump on the bottom so that it does not need to be primed during initial setup. However, for some siphon type setup, it is possible to only prime it once, and have the pump mounted on the top, about the water level. If you set your CL this way, when the pump cracks its housing, you are just end up with a burnt pump, not a wet floor.