The "Hitchhiker's Guide" to the Maxi-Stream mod - Page 23

Ball · #**551** 02/02/2006, 12:13 PM

Just curious. Have you run the props with no guard to see how much flow your guard is taking away? You say your getting 1800 GPH. Thats awesome. Would you dare esitmate how much flow the dual nitro props generate with no guard? Thanks.

Jon770 · #**552** 02/02/2006, 12:14 PM

Quote:

Originally posted by dhnguyen
Actually I was incorrect earlier. the Nitro Hammer props are not 1.5" they're 1.25" I think. Still great flow and much quieter than the Dumas 1.25"

I did my mod on a 900 w/ a single prop Dumas (since I destroyed all the Nitros I ordered trying to widen it to 3/16). I was very upset with the noise that it creates...it's not too noticable with the lights/fans on, but it annoys the h*** out of me at night when it's dark. It kind of sounds like a humming/buzzing noise...do you think it can be from the Dumas props, or something else like not being perfectly centered. I "measured twice and cut once", so I think I'm good on the cuts, but am willing to try again. You think it might be better by just swapping out with Nitros?

TA · #**553** 02/02/2006, 12:21 PM

Quote:

Besides getting the most flow out of the mod, my other goal was to have something that's as small as possible without compromising the flow. My latest PVC housing is exactly 2 inches in length and the entire thing is not much larger than what the original Maxijet.

Is that with the MJ400, MJ900, or MJ1200? One prop or two with the "latest PVC housing"?

After reading through this, and other MJ mod threads, I decided to give it a try. My goal is similar to yours.....I'd like to keep it small without compromising too much flow. I'm not looking to win a MJ mod flow competition...just get a little more flow out of these things while keeping it compact. I have an MJ900 and an MJ 1200 to work with. Figured I'd use 1 or 2 of the 1.25" Dumas props (can get local for $1...Nitros not available local) with 1.5" PVC housing...thats it.

Any other suggestions on keeping it small?

Critter · #**554** 02/02/2006, 12:32 PM

Does it make the same noise if you hold it freely in the water... It may be touching the tank and because it does vibrate it would make a buzzing sound. If it makes the same noise freely, then I would say you might want to check the centereing out.

Quote:

Originally posted by Jon770
I did my mod on a 900 w/ a single prop Dumas (since I destroyed all the Nitros I ordered trying to widen it to 3/16). I was very upset with the noise that it creates...it's not too noticable with the lights/fans on, but it annoys the h*** out of me at night when it's dark. It kind of sounds like a humming/buzzing noise...do you think it can be from the Dumas props, or something else like not being perfectly centered. I "measured twice and cut once", so I think I'm good on the cuts, but am willing to try again. You think it might be better by just swapping out with Nitros?

dhnguyen · #**555** 02/02/2006, 12:32 PM

Quote:

Originally posted by Jon770
I did my mod on a 900 w/ a single prop Dumas (since I destroyed all the Nitros I ordered trying to widen it to 3/16). I was very upset with the noise that it creates...it's not too noticable with the lights/fans on, but it annoys the h*** out of me at night when it's dark. It kind of sounds like a humming/buzzing noise...do you think it can be from the Dumas props, or something else like not being perfectly centered. I "measured twice and cut once", so I think I'm good on the cuts, but am willing to try again. You think it might be better by just swapping out with Nitros?

Th Nitros are definitely quieter than the Dumas especially when used in the double pop design.

With just the single prop though, the Dumas is still pretty quiet. I suspect that somehow your rod and/or the PVC housing isn't quite as centered as it should be hence the noise.

There will always be some humming from these mods because of the propellers but you can use a propeller balancer to decrease this greatly too. It also help to sharpen the prop blades as best as you can

D.

Brent Thomann · #**556** 02/02/2006, 12:34 PM

Quote:

Originally posted by TA
Any other suggestions on keeping it small?

if your asking me that would be impossible, he he.

use your MJ900 and dual 1.25 nitro props to get the most flow out of the 1.5 PVC. don't waste your time with the smaller Dumas props.

Jon770 · #**557** 02/02/2006, 12:34 PM

I was worried to sharpen w/ my rotary b/c I don't want to mess up the balance of the prop...

don't have to worry about that?

dhnguyen · #**558** 02/02/2006, 12:38 PM

Quote:

Originally posted by TA
Is that with the MJ400, MJ900, or MJ1200? One prop or two with the "latest PVC housing"?

After reading through this, and other MJ mod threads, I decided to give it a try. My goal is similar to yours.....I'd like to keep it small without compromising too much flow. I'm not looking to win a MJ mod flow competition...just get a little more flow out of these things while keeping it compact. I have an MJ900 and an MJ 1200 to work with. Figured I'd use 1 or 2 of the 1.25" Dumas props (can get local for $1...Nitros not available local) with 1.5" PVC housing...thats it.

Any other suggestions on keeping it small?

That was with the double propeller design on a MJ900
If you're using 1.25" props, you can actually make the housing even smaller by using a 1.25" PVC pipe and just use a test cap to attach it to the MJ body (just glue the test cap onto the 1.25" PVC). But this would not allow as much flow as the 1.5 PVC pipe.

When my wife comes back some time next week from her Sea World/Disneyland trip with the kids, I will get the camera and upload some new pictures of what the housing looks like. Honestly it's not very large or unsightly at all.

D.

dhnguyen · #**559** 02/02/2006, 12:40 PM

Quote:

Originally posted by Jon770
I was worried to sharpen w/ my rotary b/c I don't want to mess up the balance of the prop...

don't have to worry about that?

Don't use the rotary tool. You should use 600 grit sand paper or a small file to sharpen the blades.

dhnguyen · #**560** 02/02/2006, 12:46 PM

Quote:

Originally posted by Ball
Just curious. Have you run the props with no guard to see how much flow your guard is taking away? You say your getting 1800 GPH. Thats awesome. Would you dare esitmate how much flow the dual nitro props generate with no guard? Thanks.

I would have no idea actually

The double Nitro prop design is just too strong for the thing to keep inplace inside the MJ body to spin without a guard. Everytime I tried it the whole magnet would just shoot out completely.

Now the Dumas 1.75" propeller, I can tell ya that it kicks some serious butt in terms of flow. Too much in fact for my puny 55g tank.

D.

GROSSR · #**561** 02/02/2006, 01:09 PM

Quote:

Now the Dumas 1.75" propeller, I can tell ya that it kicks some serious butt in terms of flow. Too much in fact for my puny 55g tank.

What size tank do you think this would work on?

I was looking to do this 1.75 mod with a mj900 dual dumas on a 90 with wavemaker.

All I need is Tim Allen ooohh aaahh

Hey have you got the MJ900 with the dual dumas on a 90 or do you have the dual nitro turboed on the mj1200 with a wavemaker ooooh aaaah .

dhnguyen · #**562** 02/02/2006, 02:50 PM

For a 90g tank, I'm think 2 MJ900's with single 1.75" Dumas props. Each on opposite side of the tank pointing at each other. Yeah... That should do nicely.

D.

Shawnts106 · #**563** 02/02/2006, 03:12 PM

hey...

I just relized something...

Hey "D"

how long is the Carbon rod? and how long do you cut the 3/16 inch rigid?(duel nitro) (mj1200) how long for the flex?

I also want to know if there is someway I can make a stopper using the rigid...

have my crossbrace rigid airline and then a .5inch peice glued on one end inside?

do you think that would work for a Propeller stop?

How long do you make the PVC housing??? does it matter? how short have you experimented with it?

just curious questions again!

Critter · #**564** 02/02/2006, 04:19 PM

I tried that and the prop snaped off the little glued on piece... What I did was I just drilled a hole 3/16 just below the cross brase and stuck a 1/4" piece or so of rigid tube in there as the stop. works great.

Quote:

Originally posted by Shawnts106
hey...

I just relized something...

Hey "D"

how long is the Carbon rod? and how long do you cut the 3/16 inch rigid?(duel nitro) (mj1200) how long for the flex?

I also want to know if there is someway I can make a stopper using the rigid...

have my crossbrace rigid airline and then a .5inch peice glued on one end inside?

do you think that would work for a Propeller stop?

How long do you make the PVC housing??? does it matter? how short have you experimented with it?

just curious questions again!

Shawnts106 · #**565** 02/02/2006, 04:40 PM

WO!! yeah.. ok! NOW WE ARE COOKING WITH PAM!

alright.. you got a picture so I can see what exactly it looks.???

Quote:

What I did was I just drilled a hole 3/16 just below the cross brase and stuck a 1/4" piece or so of rigid tube in there as the stop.

below the top or bottom of the crossbrace?

could I use the same 3/16 inch Rigid instead of the 1/4th?

could you use flex tubing???

let me know what you think

Ball · #**566** 02/02/2006, 04:44 PM

I got some 3/16" rigid tubing and the carbon rod will not fit inside. Anyone else have this problem? Are there different inside diameters to the rigid tubing?

dhnguyen · #**567** 02/02/2006, 04:52 PM

Quote:

Originally posted by Ball
I got some 3/16" rigid tubing and the carbon rod will not fit inside. Anyone else have this problem? Are there different inside diameters to the rigid tubing?

What kind of rigid tubing are you using? If you use the regular 3/16" rigid airline tubing sold in LFS, the carbon rod will fit through easily.

D.

Ball · #**568** 02/02/2006, 04:55 PM

Thats exactly where I bought it. I tried drilling it out, but it melts and warps to easy.

I had to place on order from Drs. Foster, so I ordered me a length of their 3/16" rigid tubing. Hopefully that will work.

dhnguyen · #**569** 02/02/2006, 04:57 PM

bought mine at Petco

Jon770 · #**570** 02/02/2006, 05:02 PM

Got mine at Petsmart...I think it cost less than a buck.

jdieck · #**571** 02/02/2006, 07:51 PM

Ball / dhnguyen:

Well after reading most of this thread and all the mods and improvements I have a couple of comments that may explain why some mods get better results than others.

There are two that you may have already noticed to boost performance besides using a double prop:

a) The more inlet area the more flow.
For review sake is to say that the design issue being addressed here is that for the same amount of volume the inlets area shall roughly be equal to the outlet area multiplied by the ratio of the increase in fluid velocity.
In other words, if you increase the water velocity by a factor of 10 then the inlet openings sectional area shall be 10 times larger than the outlet area!
Taking Ball's idea of the reducing fitting as the housing I will just turn it around and use the larger diameter on the pump side while the smaller diameter towards the outlet. This configuration will allow for more and longer slots for the inlet than can be possible by using a stright housing (a coupling or a piece of PVC pipe) and of course more than using the reducing housing with the small diameter toward the pump.

b) I think it was shnguyen ho noticed that when the slots or inlet orifices extend forward beyond the location of the prop the flow is increased. This could be explained by the creation of an eductor effect. Slots at the sides and slightly forward of the prop will allow for the higher flow in the outlet and not the prop itself to dragg in additional flow. So by playing with the lenght of the slots you can increase the flow further but at some point it might reduce the flow velocity so the trick will be to find the optimal lenght for the distance to be reached by the outflow. Longer aquariums you may want higher velocity but less flow, shorter aquariums you may want higher flow but less velocity.

There are some other areas that could be experimented with, as an example: The flow coming out of the prop follows the pattern of a corkscrew swirling around. This swirling effectively shortens the reach of the flow. That cen be partially counteracted if the front brace supporting the end of the shaft can be made as two or three vane shaped flat surfaces installed parallel to the housing. These flat vane surfaces will serve three purposes, will support the front bearing and also will reduce the swirling motion of the discharged flow and work as stoppers in case the start up is in the wrong direction.

So there it is, those were the coments I wanted to make in case you feel like experimenting a bit more.
Enjoy!

want2reef · #**572** 02/02/2006, 08:38 PM

I have two maxi-streams in my 120G. One has two dumas props and the other has two nitro props.

The two nitro's put out way more flow, and more of a dispersed flow than the dumas props.

Just thought I'd share a little info.

dhnguyen · #**573** 02/02/2006, 09:05 PM

Besides the actual PVC housing, the size and pitch of the propellers play a BIG role in the flow rate.

1.25" Nitros are better than 1.25" Dumas
But 1.75" Dumas kicks arse all

Critter · #**574** 02/02/2006, 09:15 PM

The hole was drilled just below the cross brase, the hole is 3/16 to accomadate a piece of rigid tubing. the legnth of the rigid tubing is about 1/4" I'll try and get a pic. Lol but i'll probably snap the hanger off the pump trying to get it out.

Quote:

Originally posted by Shawnts106
WO!! yeah.. ok! NOW WE ARE COOKING WITH PAM!

alright.. you got a picture so I can see what exactly it looks.???

below the top or bottom of the crossbrace?

could I use the same 3/16 inch Rigid instead of the 1/4th?

could you use flex tubing???

let me know what you think

Critter · #**575** 02/02/2006, 09:31 PM

ok pics... my camera is hit or miss... not the best pics but I think the show it well enough...