DIY Group Project - Eductors

[Little Luey]

Does the length of the hose barb connection need to be longer or shorter than the other 2 pieces?
I had put one of those barb coneccions on my return just to shot water more forcefull but I think I could biuld an eductor myself.

[Geoff]

OK, some of you may recognize the following info.

The eductors are composed of only 3 pieces. I was able to find all of them at Lowe's. No glue is required! these all use a 1/2" mpt connector to connect to your plumbing. so if you have 3/4" plumbing a 1/2" FPT to 3/4" adaptor would be needed.

Parts list 1/4":
1/4"X1/2" nylon barb to MIP adaptor A-193B made by Watts
1/2"X1/2" slip to FPT coupler PVC
1/2"X3/4" MPT to slip adaptor PVC

Parts list 3/8":
3/8"X1/2" nylon barb to MIP adaptor A-300 made by Watts
1/2"X1/2" slip to FPT coupler PVC
1/2"X3/4" MPT to slip adaptor PVC

Parts list 1/2":
1/2"X1/2" nylon barb to MIP adaptor A-387 made by Watts
3/4"X3/4" slip to FPT coupler PVC
3/4"X3/4" MPT to slip adaptor PVC

Construction is simple, and the same for all 3. The coupler is the nozzle extension. This acts as a longer travel area so that the pumped water will pull more water from around the barb. The non barb adaptor is drilled in order to allow the water be pulled in by the barb. I drilled 8 holes each 3/8" in diameter. The more holes in this the better. This is the cool part. The barb adaptor fits perfectly inside the drilled adaptor. The barb sticks into the MPT part of the adaptor. I have tried cutting of a section of the barb to see if it helps and it seems to. Right now I have it so the barb ends where the MPT part of the adaptor starts. This goes along with Weathermans notes earlier. the longer the pull area in the eductor more water that can be moved.

That Is It!

now how do you know which is the right size for you? any guesses?

G~

[Wiskey]

now how do you know which is the right size for you? any guesses?

Well, you need to build backpressure behind the educator, so I would assume a pump with a slower flow rate would require a smaller nozzle size to build that pressure comming out of it. Close?

Thanks,
Whiskey

[Wiskey]

My pump has a 12.5 foot cutoff, that is problably about 6 PSI max, would it be worth it to try this?

Thanks,
Whiskey

[Geoff]

before we get into the differences in the nozzle sizes.

why would we want an eductor on the return or on a the outlets of a CLS system? what is the difference between an eductor and a PH with a tiny outlet port?

G~

[VWD]

No not missing a piece, I just falling behind. LOL

Originally Posted by Geoff

OK, you all. you are getting ahead of the game.

Vince, you are missing a piece.

here is an exploded view of mine.



G~

[Wiskey]

Originally Posted by Geoff

before we get into the differences in the nozzle sizes.

why would we want an eductor on the return or on a the outlets of a CLS system? what is the difference between an eductor and a PH with a tiny outlet port?

G~

The educator takes the extra flow that is created and directs it forward, rather than the water just spinning in small circles around the output.

Close?
Whiskey

[Wiskey]

Originally Posted by Wiskey

My pump has a 12.5 foot cutoff, that is problably about 6 PSI max, would it be worth it to try this?

Thanks,
Whiskey

Any idea?

Thanks,
Whiskey

[Weatherman]

Originally Posted by Geoff

before we get into the differences in the nozzle sizes.

why would we want an eductor on the return or on a the outlets of a CLS system? what is the difference between an eductor and a PH with a tiny outlet port?

G~

If the eductor is designed well, it should allow for the conversion of a narrow fast jet of water into a broader, more gentle flow.

[Weatherman]

Originally Posted by Wiskey

Any idea?

Thanks,
Whiskey

Probably not worth adding an eductor to a pump like that. Flow from the pump would be choked off so much by the eductor nozzle that you'd end up getting less flow out of the eductor than out of the unrestricted output of the pipe.

[bluediscus84]

hi there all i am just starting up my reef tank as you all might no, is placing eductor's in your tank a great idea? i sort of understand them but i dont at the same time. I basically go the drift that they move the water better and therefore create a better current movement? is this on the right track? Cheers for all your help guys as well it is greatly app.

[Geoff]

Originally Posted by Weatherman

Probably not worth adding an eductor to a pump like that. Flow from the pump would be choked off so much by the eductor nozzle that you'd end up getting less flow out of the eductor than out of the unrestricted output of the pipe.

this is what generally happens. there is a fine line on where the eductor will work properly and when it is just limiting your flow more than if it were a straight outlet.

putting an eductor shaped outlet does help in diffusing the stream coming out of a nozzle though. it does not take much pressure difference to cause a pull in the surrounding water. this pull is what disrupts the stream out of the nozzle causing the stream to spread out and become cone shaped. this is where it can be a benefit even if it is not really pulling in the 4-5X that it should if it were a higher pressure pump.

G~

[thebutler4]

Well .. I have a MAG24 and a Quiet One ... what pump would be better for this project?

The Mag is currently my return pump .. and quiet one is sitting idle at the moment ... but it will push 810GPH at a 3' head ...

[Weatherman]

Originally Posted by bluediscus84

hi there all i am just starting up my reef tank as you all might no, is placing eductor's in your tank a great idea? i sort of understand them but i dont at the same time. I basically go the drift that they move the water better and therefore create a better current movement? is this on the right track? Cheers for all your help guys as well it is greatly app.

Here’s my reasoning for the use of eductors:

I want 3000 gph flow in my tank, to keep my coral happy, but I only want 700 gph flow through my sump to cut down on microbubbles.

How do I do that with one pump?

I could compromise, and get a pump that runs around 1500 gph, but then I’d have too little flow for the main tank and too much flow for the sump.

So, what do I do?

I get a pressure-rated pump, capable of running about 1000 gph at 4’ head, and put eductors on the return lines. The nozzles on the eductors will throttle the flow through the pump (and sump) to about 700 gph, and the mixer and diffuser on the eductor will enhance the flow out of the eductor cone by about 4-5 times the flow through the eductor nozzle (2800-3500 gph).

The result is the best of both worlds, all through the magic of the remote conversion of potential (pressure) into kinetic (flow) energy.

[wharyat]

Just got done with some drawings to help supplement.



Assembled View


Exploded View


Full Section (cut in half)



Here is the eduactor; but with a modified intake. Instead of just drilling the MPT x Slip fitting, a dremel is used to make a larger intake; increasing flow (unless the drilled version is not limiting, i.e. lower pressure). This version would most likely need to be glued.

Any intake design will work, some may be better than others. Experiment and share your results.