Quote:
Originally posted by fhorst
I don't get it.... The Johnson is rated for 70 watts...
2.0A * 12v = 24 watts? @ 318 GPH = 3 times better then the MCP600? at a bit more then double the wattage?
So one Johnson pump should outperform 2 MCP600? and use only little more power. right?
If this is surely the case, I will stop waiting for rev2 of the MCP (who will have a 0.5 meters better head) and get me 2 mag driven Johnsons from surplus! (one as backup, as they seem to fail a lot)
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Indeed.
The difference is that this particular Johnson unit (Co30) has an impeller that's directly driven by the motor, where the Swifty's MCP600 is magnetically driven.
So it's more efficient to drive the impeller directly, but it adds to the complexity: everything has to line up right, otherwise it'll leak, as this unit seems to be.
So if you can handle the lack of reliability of the Johnson (and are brave enough to experiment with a patch or repair), then the Johnson is for you. Otherwise, stick with the trusted mag-drives.