Is it because you have a mag 5 and you don't have a 3??
Cause IMO a 3 is already more than enough, if you hafta buy a new one, then a 5 is just redundant.
well i will have a extra mag 5 and was goning to put it on the skimmer and take off the 3.
i have a tank i want to use the mag 3 on and the mag 5 is too much for that tank.