overflow prevention

I don't have pictures as I read about it on ReefCentral awhile back. I'm trying to find the exact thread. The guy had measurements regarding the hole size in the Mag 3 outlet vs the Mag 5. The fact that the mag 3 and 5 impeller have the same part number confirms that.
 
The best way to prevent overflow is to run your return pump high in the sump. This way you cannot empty the contents of your sump back into your display... trust me I have a large sump.
 
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