View Full Version : Help with a MJ1200 PLEASE

01/07/2008, 11:15 PM
Ok I am looking for a way to use my MJ1200's with my aquacontroller. I have two shroud modded mj's and that makes them flow directionally according to the way the impeller is spinning. Every time you power them off then on again they switch direction. This would be fine but I want them mounted in the corners so I need them to power off then power back on turning the impeller the same way. can I mod them to do this and if so please explain in detail or just call me, pm me and I will give you my #.

01/07/2008, 11:27 PM
They usually start in either direction randomly unless the impeller finds an obstruction in one direction then it will turn in the oposite direction. Lok for the MJ mod and how it uses a stop to stop the impeller if turning in the wrong direction.
The Tunze does the same thing but has a clutch built in into the impeller shaft. If the impeller turns in the wrong direction that trigers a mechanism that moves out a break like pin that drags against the impeller housing and stops it until it restarts in the right direction.
By the way, modified MJ with propellers can't be used to be turned on and off constantly so they are no good for a wave maker.

01/07/2008, 11:50 PM
Thanks for your advice do you have a link for this mod, but I disagree with you on the using MJ's as wavemakers. I use them on my smaller tank un-modded for two years now on 20min off 20min. and at the price I can get them at if they only last a year I am fine with that.

01/08/2008, 12:12 AM


Not modified they can be used as wave makers, once they are modified they will not last.

01/08/2008, 12:33 AM
no no my mj mod is not like these. I just cut a rectangular port where the stock small tube came out. so is there any way to stop the stock impeller and make it turn the way I want it to

01/08/2008, 12:49 AM
I think you could think of a way to have a stop in the outlet that will stop the impeller in one way but not the other. something that is in angle to the impeller circunference.
Alternatively I would think of using a mj 600 impeller in a 1200, that will keep a gap between the housing and the impeller were you can insert a pin, when the impeller rotates in one direction it tends to pull upwards out of the housing thus hitting the pin and stoping once rotates in the other direction it will tend to run against the bottom of the housing thus not hitting the pin.

In any case hitting that stop so often is what prevents the mods from lasting long enough.

01/08/2008, 04:16 PM
Thanks I will try to figure out something