 | |  | |  | |  | |  |
 | |  | |  |
I will continually update this page as people ask questions. There is often more
than one answer to a question but I am going to give answers based on what I
would do. This in no way means it is the “right” way it just means this is what I
would do. I hope that this page will save both of our time .
I give absolutely no promises that you will be successful at this. I can however guarantee that there is an
extremely long list of people on Reef Central that have been successful and the thread has generated around
100,000 views at the time that I wrote this. That kinda thread isn't generated off an idea that doesn’t work for
most the people who try it. This is a do it yourself project with do it yourself results . The time and effort that you
put into this project will have a direct result on how the mod performs and that is out of my hands. I make no
attempts to sell this as my product I am just a parts supply house for this mod. Previously you had to order all the
parts from different sources, pay shipping a handful of times (where shipping is often 2-4 times the cost of the
item you want), CoD for octura props, buy a whole case of welding rod just to get one 4 inch piece …. This is a
attempt to alleviate that problem and make this project easier and cheaper.
There are so many sizes of props and types of housings, what do I need for my MJ ?
It’s really more simple than it seems.
The MJ 900 can only run the smaller sized props like the Octura 1435 and the 2035. Because the props are
smaller in size they can fit right inside the SCH 80 pipe so you can use the small sized housing. I find the 1435
to be the most reliable and the most forgiving to small mistakes. The 2035 will give more flow but will not be as
forgiving to small mistakes when you are building them.
The MJ 1200 can run both the small and large size props. The large props are the Dumas 3004 , Octura 1240
and 1440. Because the props are larger they will not fit inside the pipe so we use a SCH 80 pipe coupler to
enlarge the housing. Many of use find the Dumas 3004 to have the most flow , be the most reliable and
forgiving. Theoretically both the larger octuras should have more flow because of the much higher pitch but it’s
really difficult to accurately measure flow in the home environment. I personally always use the Dumas 3004 on
my 1200’s unless I feel like messing around or I am testing a new fancy housing.
I want to build a mod for my 900, can you give me a shopping list ?
This is a list for the precut parts , you can replace some of them with your own parts if you wish. You will need a
Small Pre cut housing , A Centering cap for the small housing, a small piece of 3/16" acrylic rod, Stainless steel
shaft, Rigid 3/16 airline, a prop (octura 1435 or 2035) Gel super glue and some soft airline or the black airline
that came with the MJ.
I want to build a mod for my MJ 1200 can you give me a shopping list ?
First off, you can use the small housing parts above with the 1200 if don’t need as much flow but the 1200 has
enough power to also run the large props. To run the large props you need a Large pre cut housing , A large
centering cap, stainless steel shaft, Rigid 3/16 airline, a small piece of 3/16" acrylic rod, a prop (dumas 3004,
Octura 1440 or 1240), Gel super glue and some soft airline or the black airline that came with the MJ.
How do I mod my MJ 600 and lower ?
I have no clue , I have yet to mess with them. I’m trying to focus on one thing at a time. I’ll get to it someday.
I got the shroud in the mail today but it doesn’t fit on my MJ….
You need to take the rubber O ring off the MJ or it wont fit. This is the source of 95% of the emails I get on this
topic so I will say it again. You need to take the rubber O ring off the MJ or it wont fit : ) They are also meant to fit
rather tight so it may very well take a bit of force to get it on. This is good because once it is on it is not going to
come off while in use. Keep in mind that this is the same pipe that everyone is using for this project so if it really
doesn’t fit at all then you have the miracle odd sized maxi jet. That said , PVC pipe is extruded so the inside
diameter will never be accurate or the same from one piece to the next. That means that some will require more
force to get on than others , there is nothing I can do about this so please don’t complain to me about it : )
I don't own any tools and just can’t figure this out , If I send you my MJ will you mod it
for me ?
Sorry , I just don’t have the time for this and plainly put, this is a do it yourself project , that’s half the fun . If ya
want a premade product there is no shortage of them out there, get a tunze or seio .
What is the stopper and how do I use it ?
Because the maxi jet runs on alternating current (AC) power it can spin both left or right and will do so randomly
when you first plug it in. if it starts going the right way then perfect but half the time it will start going the wrong
way and end up sucking water in the front and blowing it out the fins on the side. This is where the stopper
comes in. the stopper is simply a piece of acrylic rod shoved through the side of the housing. I drill a 3/16” hole
about a 1/8” below the top of the housing (just under the cap) and glue a ½”-1" piece of 3/16” acrylic rod. What
happens when the pump starts the wrong way is it pushes the whole impeller up towards the cap when this
happens the prop will slam into the stopper (acrylic bar) and bounce back the other way and start running in the
right direction. This is extremely easy to implement and works very well. Some people have found with the
octura props that you don’t need a stopper because the ends of the prop extend up and actually slam into the
centering cap itself. I personally always use the stopper bar because it works so well , costs almost nothing and
takes about 20 seconds to install . Mother always said “if it an’t broke don’t fix it” : )
Are you ever going to sell fully precut kits ?
I doubt it. I simply don’t have the time to do as much as I am doing now much less add anything else. Also, If I
precut everything and glue most of it together, it changes this from a supply house for a do it yourself project to
an actual product that I am selling. Anyone who is unable or unwilling to cut plastic tube or carbon fiber rod
maybe shouldn't do this project anyways : )
Can i use this on a wave maker ?
I personally wouldn't as I don’t want to hear the prop click every time it turns back on. I think it will also ruin the
prop faster . Some people do it anyways. If I were to do it on a wave maker it would be a DIY one where one
pump is on 8 hours, the other is then on 8 hours and then both on for 8 hours. In my personal opinion,
conventional wave makers are a joke anyways. Real productive flow patterns in hard to reach areas like behind
your rock can’t be produced in the 30-2 min second blasts . I don’t think a pump should be on for less than 10-
20 minutes before being turned off if you want to generate a real flow pattern behind the rock and less
assessable areas. Getting flow going the open areas of the tank is no big challenge, It’s getting flow to the
stagnate and hard to reach areas that is hard, 30 second bursts just wont do it.
I'll Add more as they come to me : )