Recirculating Venturi Mod for Maxijet

[minibowmatt]

I have an excalibur SV1 skimmer that uses a rio 800 RVT pump. Well I wont put a rio in my tank, so I started to mod a MJ with the same basic mods that the RIO RVT has. I used a piece of 3/4 ID Acrylic (fits snug on the Inlet of the MJ) Drilled two 1/8" holes in the Acrylic and cemented two small 1/8" ID rigid acrylic tube (about 1/2" long) on to those holes. The idea is you connect airline tubing to the 1/8" tube, and use the second as a recirculating tube- takes excess air from the outlet of the MJ and puts it back to the inlet side... It should work well.

 

[Anonymous]

You may need to play around the design a little if neither of the 1/8" tubes have any suction when the Maxijet is on.

Some people push the tubes down a little, and cut the ends at an angle to get more venturi effect out of it.

 

[minibowmatt]

COol Thanks for the insight.. I just came up with this in like 20 minutes, I havent even had it in water yet!
So you think the air tubes should protrude through the 3/4" tube? and be cut on an angle (facing the pumps). Can you run an airpump to one of these to increase efficiency? BTW I will be running the MJ Needle wheel (bioball) mod as well to help break up the bubbles more.

 

[Anonymous]

Yes, an air pump will help injecting air into the skimmer. However, that kind of defeat the purpose of venturi, and you introduce a variable into the system that may make it more difficult to tune the skimmer for optimal skimming efficiency.

 

[hfmann]

Very cool Matt!

I've been trying to figure out exactly the same thing. My Rio 800 is a piece of junk and I love the MJs.

What model MJ are you using and how are you hooking up the recirculation tube?

BTW I will be running the MJ Needle wheel (bioball) mod

I didn't know there was one. Where'd you get it?

FWIW but unrelated to your exact project, I was able to "glue" a 1/2" pvc female adapter to the input port of the MJ. That enabled me to attach a small length of 1/2 pipe and with another female adapter on the end, I screwed on one of those small bulkhead strainers. Now with this MJ I pull in water from the very bottom of my tank and distribute it at the top.

Another MJ mod I've found helpful - The right size John Guest fitting will slip securely over the output of the MJ. Then you can easily attach other tubing to route the output where you want. I use this configuration along with the glued female pvc adapter as a recirculation pump for my Kalkwasser reactor.

Those Maxi jets are great and I'm anxious to hear / see more of your modification.

Take care,
Hal
_________________
economic depression

 

[Anonymous]

Regular clear vinyl tubing will go over the MJ very well, particularly if you put a metal band with screw around it, FWIW.

 

[minibowmatt]

Thanx. I havent done the recirc. part yet, as I didnt have airline tubing this afternoon. I will try and hook that up soon. and check it out.

 

[hfmann]

Matt,

Where'd you get a needle wheel for the MJ?
_________________
Mercedes Fintail

 

[minibowmatt]

Its a mod.
Cut a bioball in half, break off a bunch of the "needles" and stick it over the fins of the impellor of the MJ. There is a detailed thread on another site, but I dont have a link (I'm behind a silly firewall and cant get to RC or RM)

I am using the MJ 1000 model.

 

[minibowmatt]

here is a newer design- based off of 7E's ideas. What do you think?

 

[Anonymous]

Lookls good!

The mod is not needed for the port that get water from the PH output, but this way, you don't have to worry about which port you use for the air, and which for the recirculation.

So the real question is.... does it work?

 

[minibowmatt]

I wont know until I get home. Last night, the one I built yesterday did not have enough suction.. like you figured. This one does seem better.

 

[minibowmatt]

well It does work. I am getting a full stream of bubbles out of the airtube, and a nice amount of chopped fine bubbles thru the recirc tube. I did have to obstruct the intake a bit, or I wouldnt get enough suction.

 

[Anonymous]

That will be your beta version. Want a better one?

Here you go.
1, move the restriction from the intake closer to the power head to where the venturi air intake is.

2, make the recirculation input flush against the restriction instead of protruding out like the air intake, or alternatively, remove it altogether since you won't need it when you have the bioball chopper.

3, can't see the restriction on the intake clearly, but when you move it to the section of the venturi air intake, make it more hydrodynamic by smoothing out the sharp edges.

 

[minibowmatt]

Ok.. Im down for this..
let me make sure i know what your saying..

I will make a smaller unit with the Air intake venturi as close as possible to the MJ intake (gray piece). I am going to leave the recirc in place, but move it closer to the pump, and mount it flush--not protruding into the tube.

As for the obstruction, right now it is just a piece of rubble. the pump sucks the best when the intake is obstructed almost 50%, so I will create an acrylic cap with a vertical slot about 1/4" wide, and put it onto the mod...

Does that sound correct? look for a prototype this afternoon!

 

[minibowmatt]

here we go.. shorter, closer, and obstructed.

 

[Anonymous]

What I mean is that move the obstruction inside the venturi piece, and let the venturi air intake to go thru the obstruction.

 

[minibowmatt]

OOOHHH.. I C.. .Lemme take another crack at this.. Good thing I have like 10Ft. of this tubing and they only take 5 min. to make!

 

[hfmann]

What are you using to glue the rigid tube into the MJ for the recirculation loop?

Hal
_________________
Danish Forum

 

[Anonymous]

Looks like he just drill a nice hole and put in some cement... don't have to be perfectly water tight since the MJ going to be underwater anyway... right, Matt?