The "Hitchhiker's Guide" to the Maxi-Stream mod

[Jon770]

Mod Placement

Mod Placement

Question: Assuming I don't have any areas that require more/less flow, what do you think is the best setup for 2 of these Mods (single Nitro props on MJ 900's) in a 4' standard 75G tank?

I currently have one of these mods already in the tank (#1 in pic below):

My fish seem to love the flow that is created across the front of the tank, and they swim in it all day long...so I want to keep at least one mod flowing across the front of the tank. Now that my second mod is ready to go in the tank, I don't know what to do with it. I was originally going to put it in the back-left corner facing the right of the tank (as seen in #2 in pic), but now I am worried that it will make too much of a 'whirlpool' effect in the tank. Anyone have this problem, or think it will be a problem?

If I put one in the back-right corner facing left, will that create a weird flow when the two meet/hit on the left wall of the tank? Anyone have any other setup ideas that would help me out?

 

[dhnguyen]

It will indeed create a whirlpool effect. Why not just point the 2 against each other ot help randomize the flow a bit?

D.

 

[jrcastro]

<a href=showthread.php?s=&postid=6835937#post6835937 target=_blank>Originally posted</a> by dhnguyen
By the way guys. I noticed something today while testing out a couple mods.

The MJ900 runs MUCH smoother and quieter than MJ1200. I tested this using the same exact prop assembly (well except the MJ impeller magnet itself) and housing tested on both MJ900 and MJ1200. The MJ900 is really very quiet whereas there is a slight whirl/hum from MJ1200.


D.

What prop assembly are you referring to?

Are the MJ 1200 / MJ 900 impeller magnets interchangeable?

Will the MJ 900 run the 1.75" dumas prop?

Thanks

 

[Jon770]

<a href=showthread.php?s=&postid=6838749#post6838749 target=_blank>Originally posted</a> by dhnguyen
It will indeed create a whirlpool effect. Why not just point the 2 against each other ot help randomize the flow a bit?

D.

Would you place both near the front wall facing eachother, so they hit at the center? Or would you put one in front/one in back, both facing a single wall (as mentioned in my previous post)...and they would hit at the other end of the tank?

If I put them both on the front facing eachother, do you think that will make me lose the stream that the fish swim in (b/c they are so close together and the flow will be COMPLETELY random)?

 

[hahnmeister]

the 1200 is more of a high-wattage/high-head powerhead compared to the others...that is why it uses so much more wattage (24w/295gph) compared to the 900 which is just 65gph less but 1/3 the wattage. This is also what makes the MJ1200 the pump of choice for protein skimmers and sump returns (HOB ones). And this is most likely what the reason is for the extra noise.

As for the carbon rod vs. steel...in looking at the carbon rod, it seems rough on the surface...and I thought this might result in more friction on the internals than a SS shaft. Any opinions?

 

[dhnguyen]

<a href=showthread.php?s=&postid=6838846#post6838846 target=_blank>Originally posted</a> by jrcastro
What prop assembly are you referring to?

D: I was testing a double nitro mod

Are the MJ 1200 / MJ 900 impeller magnets interchangeable?

D. Well if you switch the magnets, they will still run. But the MJ1200 is I think slightly stronger and could adversely affect the MJ900 motor.

Will the MJ 900 run the 1.75" dumas prop?

D: Yes.

 

[dhnguyen]

<a href=showthread.php?s=&postid=6838878#post6838878 target=_blank>Originally posted</a> by Jon770
Would you place both near the front wall facing eachother, so they hit at the center? Or would you put one in front/one in back, both facing a single wall (as mentioned in my previous post)...and they would hit at the other end of the tank?

If I put them both on the front facing eachother, do you think that will make me lose the stream that the fish swim in (b/c they are so close together and the flow will be COMPLETELY random)?

I have mine placed on each end of the tank pointing against each other not on the front glass nor the back but kinda in the middle to utilize the wide dispursed flow better.

 

[dhnguyen]

<a href=showthread.php?s=&postid=6838977#post6838977 target=_blank>Originally posted</a> by hahnmeister
the 1200 is more of a high-wattage/high-head powerhead compared to the others...that is why it uses so much more wattage (24w/295gph) compared to the 900 which is just 65gph less but 1/3 the wattage. This is also what makes the MJ1200 the pump of choice for protein skimmers and sump returns (HOB ones). And this is most likely what the reason is for the extra noise.

As for the carbon rod vs. steel...in looking at the carbon rod, it seems rough on the surface...and I thought this might result in more friction on the internals than a SS shaft. Any opinions?

Yeah there is slightly more friction with the carbon fiber than SS. After a while though, the carbon shaft will be polished enough that you won't even know the difference. The rods in my MJ mods running in my tank are smooth as can be.

One can also easily smooth down the carbon shaft some w/ some light sanding.

 

[shelburn61]

Anyone see a problem with putting slots only on the bottom of the housing and leaving to top intact so the MJ can be put closer to the surface without drawing air?

I was thinking this might create a balance/turbulence problem with the prop.

 

[dhnguyen]

You can do that assuming you still have enough inlet slots for adequate water input. I wouldn't divide the pipe into exactly 50% with the bottom 50% for slots and the top 50% intact as that would interfere with the balancing and turbulence as you suspected.

More like 20% of the pipe ontop left intact.


D.

 

[jl7854]

Hi all,

I have finally finished reading and studying this thread as well as a few others. It sure is long. I plan on making a couple of these and wanted to pose a question that if asked before I some how missed. To get the maximum efficiency it has been stated that you need to allow the water to get into the prop chamber. Almost everyone has been putting holes or lines perpendicular to the length of the housing. Probably mostly because it is easier. After looking at those other models that are not a mod and you buy from a vendor I noticed that their water intakes are parallel with the housing body. This may allow better water flow into the prop chamber. My thinking is that all these holes and perpendicular lines are like 90 degree elbows in a return line especially with the thicker walled material. Could this slow down the water getting into the chamber? Does this sound right?

When I make mine I plan on using a home made jig for my dremel that should make nice lines parallel to the length of the housing. Using a jig the pattern of the lines could be almost any shape...perhaps lines matching the pitch of the prop.


Jon

 

[dhnguyen]

Yes if you have the tool and way to cut the lines horizontally, you could fit a lot more slots and essentially increase the amount of input water. I don't think the perpendicularity of the pipe's slots would affect the water anymore on the vertical slots versus horizontal slots. The cuts are still the same unless you were to use a much thinner walled pipe for this.


D.

 

[ChemE]

What does everyone think of using this rather than slots in 2" PVC?

Buy it here...

 

[hahnmeister]

That rocks...good eyes ChemE. I bet that would save some time...attach it to a piece of 1.5" PVC with grooves for attachment. The only problem I see is how could you then make the brace to hold the shaft on the outlet end?

 

[dhnguyen]

Tried it. Didn't work too well. The inlet holes are too small (like 1/8" or so) and if you cut them out to make them larger the whole pipe becomes kinda flimsy.

D.

 

[ChemE]

Cool, back to the drawing board then.

As a general point of information, the difference between a 1.75" Dumas prop and one that is cut down just enough to fit inside 1.5" schedule 40 PVC is very very pronounced.

 

[shelburn61]

D,

What propeller/mj combinations have you found to put out the most flow with the least noise?

The 1.75 dumas on the mj1200 is loud!

 

[dhnguyen]

Double nitro props w/ MJ900 or single nitro w/ MJ600 are quietest

 

[dhnguyen]

<a href=showthread.php?s=&postid=6841974#post6841974 target=_blank>Originally posted</a> by shelburn61
D,

What propeller/mj combinations have you found to put out the most flow with the least noise?

The 1.75 dumas on the mj1200 is loud!

Ona side note, I tested the 1.75" Dumas on a MJ1200 and though there is a kick and slight hum it wasn't unbearable.

I still think your rod maybe off centered somewhere.

D.

 

[shelburn61]

<a href=showthread.php?s=&postid=6842237#post6842237 target=_blank>Originally posted</a> by dhnguyen
Ona side note, I tested the 1.75" Dumas on a MJ1200 and though there is a kick and slight hum it wasn't unbearable.

I still think your rod maybe off centered somewhere.

D.

I don't doubt it. I'm going to rebuild it. Just wondering what combo to use next time. I'll probably stick with the 1200 rather than buying the 900.