Great, cheap, and functional DIY eductors!

[liveforphysics]

Hi guys!

Eductors are a very neat tool for our reefs. They enable a pump to circulate a small amount of water at a high pressure, and turn this pressure into velocity. This fast moving water stream creates a low pressure area, which draws much more water through the nozzle. Often they operate at a ratio between 4:1 to 15:1 depending on the pressures used. Due to these nozzles being designed around aquarium pump usage, the orifice is larger than a high pressure system would use, and this lowers the ratio, but reduces head pressure against the pump. This enables a wider range of pumps to be used than normal eductors.

These are some pictures of the eductors that I used in my home reef tank. They cost me around $25 each (just for the nozzle, not including the loc-line), and they are only available in 2 sizes, both of which to large for small tanks and too small for giant tanks.

http://www.ejlin.com/albums/album35/0719071829_G.sized.jpg

So, after looking at some other DIY eductor designs, I decided that my design would need to meet a few requirements.

First, the materials cost must be under $1.

Second, it must be compact.

Third, it must be able to be scaled up or down to work with any flow needs from nano to 1000 gallon monster.

Fourth, must require no special tools and only take a few minutes to build.

And most importantly, it must actually be functional! Many designs that I've seen will not be functional, and/or will be worse than no nozzle at all.

So, here we go.

The only materials are 3/4" sch40 PVC and 1" sch20 PVC. I bought a couple of 10ft sticks at home depot for about $4 for both 10' sticks. This makes the cost per eductor about $0.15 each.

Tools are a hacksaw, a burns-o-matic torch, a screwdriver handle, and an old lightbulb. Gloves will also be nice :)

To make the convergence nozzle, heat a 1" section of the 3/4" PVC pipe, pull to stretch it as far as possible without tearing it. If you are wanting to make very small orifices for higher pressure pumps, you can snug a zip-tie down on it while it's still hot.

http://www.ejlin.com/albums/album50/P9240078.sized.jpg


To make the outer nozzle, I cut off a couple inch piece of the 1" PVC, heated it softly with the torch, jammed a screw driver handle in 1 end, and forced a light bulb in the other. After a little practice, this gave me just the shape I was looking for.

http://www.ejlin.com/albums/album50/P9240079.sized.jpg

http://www.ejlin.com/albums/album50/P9250091.sized.jpg

So, here we have some finished pieces for examples.
http://www.ejlin.com/albums/album50/P9240081.sized.jpg


I tried a couple of designs for a part to hold the secondary apature. This was what I settled on because it was very quick, easy, required no additional materials, and blocks very little flow.

http://www.ejlin.com/albums/album50/P9240082.sized.jpg

Here are bunch of finished nozzles. Notice that I'm making lots of different shapes and designs to try out what works best.

http://www.ejlin.com/albums/album50/P9250092.sized.jpg

Here is how I made the holders. The pics explain it pretty well. Very simple to make.

http://www.ejlin.com/albums/album50/P9250094.sized.jpg

[liveforphysics]

http://www.ejlin.com/albums/album50/P9250095.sized.jpg

http://www.ejlin.com/albums/album50/P9250096.sized.jpg

Here I'm laying out pieces to make many different designs of eductor.

http://www.ejlin.com/albums/album50/P9250099.sized.jpg

A little glue, and poof! All done!

http://www.ejlin.com/albums/album50/P9250101.sized.jpg

http://www.ejlin.com/albums/album50/P9250102.sized.jpg

http://www.ejlin.com/albums/album50/P9250103.sized.jpg

http://www.ejlin.com/albums/album50/P9250105.sized.jpg

http://www.ejlin.com/albums/album50/P9250106.sized.jpg

[liveforphysics]

Comming up with the construction method, experimenting with the design, and building 10 of these took me roughly 2 hours. The total project cost was $4, and I used only about 1/3 of the materials.


If anyone has the ability and time to actually quantify the flow rate differences from the different orifice sizes and bell shapes, I will mail all 10 of these away for free if you will post your findings for all to see here on the forum.

Best Wishes,
-Luke

[lvpd186]

Very interesting! A little black paint and they will look almost like some commercial units. Are you going to post some shots of them in the tank (or at least a test tank)?

[lvpd186]

What would be the best way to test? I would imagine if you took an airline hose and introduced air in to the current to show the current that you could visually test the flow between with and with out the educators.

[RWillieK]

Very cool - I might have to try these myself!

[tunaluver]

so do these just slip right on over the return lines?? or do you need to make an adapter to make it fit?

[andbigdaddy2]

Very cool cant wait to see pics on these in action looks like the only tools you need are a torch (19.99) and a hack saw (4.99-19.99) the rest are things you can find around the house.

What kinda glue did you use?

[rustybucket145]

genius.... now I gotta go look at locline fittings to see what I can come up with to attach these to 3/4" locline.

[chrisjet]

looks good, thanks - i think i will try something like this

[Theexp]

Great idea. I love this sort of project. That is fun to try out, inexpensive and worthwhile. And if it turns out you don't need it won't be a loss. Thanks alot! I might build some for my tank

[H20ENG]

Also,
If you slip (no glue) the flare onto the nozzle section, you could remove it and hit the nozzle with the belt sander to open it up more if the flow reastriction was too great. Never thought of the zip tie idea- nice.

[FunkieReefJunkie]

Ah... the smell of burning PVC. I think I will have to try this one out since I've always wanted to own a torch, but didn't have a good reason. Shhweet.

[Dustin1300]

I love the idea but what kind of paint can you hit these with that will make them look a little better in the aquarium?

[jman77]

well , it's looks like you just save me 25 bucks ...

http://www.championlighting.com/pics/plumbpics/eductor34f.jpg

[bigtex52]

<a href=showthread.php?s=&postid=10845919#post10845919 target=_blank>Originally posted</a> by Dustin1300
I love the idea but what kind of paint can you hit these with that will make them look a little better in the aquarium?

Krylon Fusion Satin Black would work well here.

[liveforphysics]

Thank you for the kind words!

In reguards to testing flow, I've been thinking about what the best method would be. I was first thinking the classic pour an icecube tray full of plaster. Weigh each plaster block and locate them in a couple places in the tank for X amount of time. Then remove, weigh them again, change nozzels and repeat. Which ever nozzle design has the lightest blocks after X time could be the winning design.

However, I realized the functionality of the eductor is going to depend so much on the pressure feeding it, that this test would only produce results for 1 type of pump, and the direction the nozzles are could be a huge player in the results if things couldn't be kept even.


So, I'm thinking the best way to do this would be a circle or square raceway tank. The cube method located somewhere on the back side of the raceway should be really consistant and accurate. Or conventional prop design flow meters would be simple to use this way as well.

Of course these only will yeild qualitative results, but for reefkeeping purposes, this is perfectly adquate.


Best Wishes,
-Luke

[H20ENG]

Luke,
You could use the plastic bag method. Get a trash bag and a timer. Stick the bag over the eductor and time how long it takes to inflate the bag. This would have to be done in an empty tank obviously, or a smaller bag and a quick trigger finger on the stopwatch.

[liveforphysics]

Well, I finally stuck one on a nozzle in my tank today. Seems to work pretty much exactly the same as the professional eductors that I have. When you put your fingers near the back area, you can certianly feel it sucking. I took a pinch of dried oyster eggs underwater next to the nozzle and released them near the side of it. It drew the oyster eggs right through the area where it should, and blasted them across the tank.

I think the cool application for these would be for the nano guys. They could make very small versions to use on the return pumps. It would reduce the overflow flowrate and noises while make a large increase in water movement without the addition of larger pumps in heat sensitive enviroments.

Best Wishes!

[andbigdaddy2]

Any pics of them in action?

[Giovanni]

Very cool. I do not use eductors, but if I did I would defiantly do this.

[ctreefer]

Very nice idea. Does anyone know some good "small" pressure rated pumps. By small I mean that consume maybe 25-40watts of juice. I might give this a try as well.

[liveforphysics]

ctreefer- Perhaps the most clever thing about making your own eductor is making the orifice size to suit your pump. If you have a low pressure pump, you can make a larger orifice to suit the pressure ability of your pump. The downside is of course a lower flow multiplier ratio. A large orifice design may only result in a 2:1 flow boosting ratio, but reguardless, you doubled your flow for a couple of dollars without increaseing heat or power consumption.


Also, if you wish to increase the head pressure ability on a pump, you can use epoxy putty to reduce the diameter of the inlet area, and bring the surface as close to the impeller as possible. Starting with a pump that features realitively tight fitting impeller housings would be a bonus as well. While you are working with the houseing, radius the outlet passage, and you may compensate for the flow lost from increaseing the head abilitys.

Just another 20mins with some frag mounting putty and a dremel sort of mod, but you may be suprized at what you can do for the pump.

Best Wishes

[liveforphysics]

I've had a generous offer from rogergolf66 who says he has both the time and ability to test the performance of the different nozzle designs. I will be sending them out to him today.

I looking forwards to seeing his results shared with the board. This way we will get some solid ideas on what shapes and orifice sizes perform best.

[jnarowe]

Nice job Luke. :)

[H20ENG]

Perhaps the most clever thing about making your own eductor is making the orifice size to suit your pump. If you have a low pressure pump, you can make a larger orifice to suit the pressure ability of your pump. The downside is of course a lower flow multiplier ratio. A large orifice design may only result in a 2:1 flow boosting ratio, but reguardless, you doubled your flow for a couple of dollars without increaseing heat or power consumption.

Luke,
I have always wanted to try this with a low pressure pump like a Dart. Paul (OM) and I have talked about this before. Even if you only get 1.5:1 its still an improvement, if you are not cutting down the original flow by restricting it that is.

[liveforphysics]

Thank you for the kind word Johnathan!

H20ENG- The return pump on my reef is a dart. I use 4 0.375" orifice eductors on the outputs. It moves loads more water with them than without them. Not just a sorta noticeable thing, but a need to re-aim them from sandstorm and water over the edge of the tank sort of flow increase.

Dart and eductors is a definate winner. Also, the pump draws about 15watts less power with the eductors installed.

I've not tried an oceans motions in the mix with a dart and eductors. After going to a VFD drive wave pulse system for my closed loop, I gave my OM's away.

Best Wishes

[Elliott]

liveforphysics: very clever and simple, wish I would have read this before buying my eductors. regarding your VFD drive wave pulse system for your closed loop, what is VFD and can you elaborate on what you are using?

also, I have eductors on the 4 return lines of my OM 4 way running on a Sequence Barracuda and the backpressure is too much for the version 2 drum to rotate. Paul at OM recommends trying a version 3 drum which I am planning to do.

[BenjieC]

<a href=showthread.php?s=&postid=10860493#post10860493 target=_blank>Originally posted</a> by Elliott
liveforphysics: very clever and simple, wish I would have read this before buying my eductors. regarding your VFD drive wave pulse system for your closed loop, what is VFD and can you elaborate on what you are using?



Here you go: http://archive.reefcentral.com/forums/showthread.php?s=&threadid=1183020&perpage=&pagenumber=1

Enjoy, I know I did.

[Elliott]

BenjieC: thank you, great read !

[coralite]

Ghetto-Freaking-Fabulous! :D

I'd love to see you play around with some eductor designs with different nozzle shapes such as a flared and a clover shaped varieties. Thanks for sharing.:strooper:

[Zucker26]

I have a 29gal display with a 10gal sump, but I'm running a 1500gph pressure-rated return pump (I know, I know, but it was only $20 and I was still in school). Since I'm circulating so much water through a 10gal sump, I have some very creative bubble traps. I have been told many times that my tank is WAY too small to need educators, and I agree. However, this post made the think...

The current coming from two returns connected to a SCWD is perfect right now without throttling the pump back, but I would LOVE to be able to cut the flow across my sump in half. I think I could make even smaller versions of your educators, then throttle back my pump by about a third, which would allow me to get rid of some of the bubble traps and maybe add a fuge.

Do you think adding educators and throttling back my return pump would be a viable way to decrease the flow across my sump while still maintaining the current in my display?

[coralite]

<a href=showthread.php?s=&postid=10868727#post10868727 target=_blank>Originally posted</a> by Zucker26
Do you think adding educators and throttling back my return pump would be a viable way to decrease the flow across my sump while still maintaining the current in my display?

Absolutely! That is a great solution you have there. It appears that you are pretty clear on plumbing concepts, I think you got this one down. :rollface:

[Elliott]

Zucker26: the interesting thing about eductors is the back pressure they cause. So, you may open up your pump even more and not increase flow through your sump, though flow in your display will be significantly increased.

[Zucker26]

As a chemical engineer, this is probably supposed to make complete sense to me, but I do have one question of clarification.

If I'm currently running 3/4" return lines, then any outlet smaller than that will increase flowRATE (velocity). If I want to maintain my current flow velocity but increase the volume of water being moved, then I could make an educator with a 3/4" outlet which would maintain the velocity of flow but increase the volume of water being pushed.

Is that correct, or is my GameDay buzz still going strong?

[Elliott]

Zucker26: an eductor works by a different principle than decreasing the size of a pipe outlet. eductors create a negative pressure area caused by the flow being pushed through them. This negative pressure is rapidly "filled" with surround water into the eductor's central stream, creating a large water mass movement. they are used primarily in large vats of paint, oil, etc. for mixing purposes. eductors will cause significant resistance or back pressure which is why one needs a pressure rated pump to drive them properly.
Now, getting back to your application, if you put an eductor on the end of your sump return your flow where the eductor is sitting will INCREASE, due to the large water mass movement it will cause. However, the flow behind the sump's pump, which is the flow across your sump will DECREASE, due to the resistance or back pressure the eductor is applying to the pump. Or you can open up the pump's outlet valve a little to compensate for the resistance and maintain the same flow through your sump.
So, yes you could make an educator with a 3/4" outlet which would maintain the velocity of flow but increase the volume of water being pushed.

[Pbrown3701]

I made one of these today for my 74 bowfront. I already had a purchased eductor running on an Iwaki 70RLT. I added this DIY version to the opposite side of the tank facing the purchased one. It seems to work every bit as good as the OEM. The flow from the DIY actually seems a little bit stronger than the original.

Thanks for the design live!

[liveforphysics]

Pbrown3701- It was my pleasure to give back to the comunity, and it makes me feel great to hear that it is working as well as your professional eductor. You are very welcome.

Coralite- You are likely the man best suited towards the tricky task of at least qualitatively evaluating the different designs of eductor. If I were to create a variety of designs and send them to you, would you be willing to test and share your results?
BTW- I really respect the work you've done with the science of the interaction between waterflow and corals. Keep up the great work!


Best Wishes,
-Luke

[coralite]

Hi Luke,
Thank you for all the kind words. I am developing a pretty thorough water flow study which will first evaluate not flow rates but "water movement" by various water pumps and their placement. Although I will be focusing on various water pumps to begin with, i do intend to evaluate water flow accessories to see how they affect overall water movement and you can bet eductors and penductors will be evaluated. However, I probably wont get a chance to do the flow accessories for awhile. However, if you wanted to cook up a few modified eductors I would be glad to give them a review and see if we can tweak the designs for different applications.

On another note, howzabout a video of the dramatic flow alternation in your tank? Put some flake food in there so we can see the flow and post it online for us to see. I have a youtube channel to use if you want to post it to a video sharing site.

[scottflanagan]

I was looking at the eductor/penductor website and they suggest using one or two at most.
I was thinking of doing 4 on a pump that is rated for 580 gph.
I am using a panworld 50px and don't want to put too much head pressure on it. I also want to direct the flow in multiple locations.

No mater how much the flow is reduced(2.5 gpm[gallons per minute] in my case w/4) it should still create that low pressure area thus pulling more water out of the tank for circulation. Correct?

Penductor's web site has a chart:
http://i47.photobucket.com/albums/f190/francisthethird/untitled.jpg

It seems they claim no mater how many GPM you force through it the gain is always at a factor of five.

Now i have only taken one physics and 2 calcs but i would think the gain would be more complex than liner equation.:reading:

If it is corect than the adition of 4 eductors would alow my 50px to circulate 3000 gph around my little tank!!:uzi:
Could this be so?

Also would it matter if they were close to the top? I would not want to pull air into my tank.

[liveforphysics]

It does workout to be a linear relationship. This is beacause you end up with an x^2 function on both the top and the bottom of the equation and they cancel, yeilding a mostly linear relationship between primary flow rate and total flowrate. I often see 5:1 as a ratio for these low pressure devices. Higher pressure devices for special applications often have very high ratios, like 50:1.

I'm figureing my copycat's of the professional designs have between a 2:1-5:1 functionality range.

The beauty of making your own comes in the ability to size your orifice to the needs of your specific appliction and pump. If you have a pump that has flow fall rapidly as head increases, simply make large orifices and you still get to enjoy a having twice the flow without needing a special pump.

The flow is also of a very nice quality for corals. Not a laserbeam to blast off coral tissue, but rather a wide turbulent gentle waterfall-like feeling that carrys for a long way through the tank due to the large mass of moving water.

I'm waiting for someone with a nano to make them from very small PVC to suit the needs of a nano.

It would also be great to see someone make one from 2" PVC to be used on the outlet of a large surge tank in a monster reef. Should help solve many problems associated with surge tanks with noise, while enableing the surge tanks to be smaller (yet mounted higher up).

Coralite- I will send you all the designs you would like, and I will be very appreciative of you taking the time to evaluate the flow increases from the different designs.

If you have an designs in perticular that you would like me to make for your tests, just let me know. They only cost pennys and take a few minutes to make. I make them on my breaks at work, so I'm actually getting paid well when I'm making them :D

[Zucker26]

I bought the PVC to make a very small one for a 12gal nanocube, and I'm also making 2 for my 29gal that I'll put after a SCWD. So far I'm simplifying it even more; all I bought were 3/4" Locline MPT connectors, 3/4" hose barbs for the orifice, and 1" PVC for the other part. On the nano, I'm using a 1/2" hose barb, and 3/4" PVC. My only concern is the pump in the nanocube, it might not be strong enough to push through the 1/2" orifice.

[coralite]

IMO, The full size eductors, 1" diameter by 4" long, are so effective that they are better used in tandem than trying to increase the size of the design. I was at Richard Harker's house when he made a cross with 1, 1" eductor and 4 x 3/4" eductor and we literally blew up a 30" cubed capricornis which was about 4' from the eductor cross! his tank is 4'x4'x24' by the way. I think he used a 1hp dophin pump. So anything larger than a properly driven 1" is gonna provide a unnecessary amount of force. However, I think small eductors are a good idea but due to viscosity forces, i doubt they will move much more water then say a regular flared nozzle.

[wmfsoll2]

This is a great project. These DIY eductors are more like the manufactured ones, the other DIY eductors that i have seen in this site that just have oles drilled in the PVC. I am curious to find out how well they Work. And also how well they work in comparison. Keep up the good work.

Thanx, Bill.

[Pbrown3701]

IMHO, 4 would be too many for anything smaller than 150 gallons or so. I've got 2 running on this Iwaki 70 (huge pump for this size tank) and I have to valve the eductors back about half way. The good thing is that i get just as much water flow as before, yet my pump has much more back pressure which means it runs at a lower amp draw - less added heat to the system and lower power bills.

[denverhoss]

I agree with the other praise, this looks like a great project to try! One question though, I've read that heated PVC releases Hydrogen Chloride or something that make great ventilation a must, and some advise a vapor mask be used. Is that correct?

[Zucker26]

Yea, when I heated it up it definitely made a terrible stink. I was outside when I did it though, so I wasn't really concerned with fumes.

I did, however, run into one small problem. When I was stretching the PVC out (I used the spout end of a funnel turned upside-down), it more compressed longitudinally then stretching out circumferentially. Now I have things that will definitely work, but they ended up much shorter than imagined and not as flared as I had hoped. Anyone else run into this?

[liveforphysics]

Zucker26- I had similar problems with the first few I made. I forgot to mention this step, but spraying WD40 on both the lightbulb I used as a swedge tool really made it slide and increase diameter much better without smashing it shorter. The secondary nozzle was easy to make once I used lube. The primary nozzle always the most difficult, as I had to quickly clamp 1 end in the vice as soon as I got the PVC warm enough, then pull as hard as I could with one arm while pulling the zip-tie shut with the other. It was kinda the sort of job an octopus would be better suited towards, but none the less one you get a method it only takes a few minutes to make one.

Please share photos of your own!

Best Wishes,
-Luke

[Zucker26]

Luke,
Thanks for the advice! As for the nozzle, I didn't have to worry about it because I modified the design slightly. Since my returns already use LocLine attachments, instead of making my own nozzles I just bought some LocLine 1/4" and 3/8" round nozzles. I'm just going to fit the eductors to the nozzles.

I also bought some double-ended LocLine attachments so can make a few others using threaded LocLine MPT's and then screwing 1/2" hose barbs on for the nozzles.

As soon as I get time to put these together I'll post some pics.

[jasonh]

Forgive me if this sounds dumb, but here's a thought I just had:

Could this be used on just a normal powerhead like a MJ600 or something?

The thought I had was to leave the MJ's outlet the same, but then make the secondary nozzle to fit over it. Seems like this wouldn't add a whole lot of pressure to an already weak pump, and just might give some type of gain.

I've got some 3/4" pvc right now I'd try with, but I don't have a torch and am strapped for cash till payday :(

[toastman]

I am sure it would help on a power head....same concepts and principals with the negative preasure area

[liveforphysics]

Jasonh- You certianly could make an eductor optimized for the pump curve of a MJ600. You would need to carefully try different nozzle orifice sizes until you found the optimization between flowrate dropping from increased head vs velocity pressure drop induced bulk flow increase though enduction area. For something like an MJ600, you would want to only drop CSA a small amount to prevent excessive head loss.

However, my advise for you would be do the "MJ-mod" to your MJ600, as it would yeild better results.

Eductors function best as closed loop outlets or return outlets.


Best Wishes,
-Luke

[jnarowe]

I installed a couple of Penductors on my two front return lines and the flow is definitely better, but at a price. The flow is extremely powerful and pointed, so I would be concerned about these being pointed towards any coral within a foot or two.

The other issue is that it reduced total flow through the overflow by quite a bit. I am not a fan of high flow through the sump, but since I feed my skimmer directly from the overflow, this could have an impact on skimming. I turned down the 2" drains to provide more water to the skimmer, and we'll see if skimmate production is affected.

This of course in no way reflects on Luke's DIY eductors, since I do not have them and don't know how they compare to the commercially made ones.

My objective was to get more flow, and in my conversation with the maker of Penductors, he told me that I would get a net increase of in-tank flow. I just don't know how to measure and verify that. Whatever the case, the flow feels like it would peel the flesh right off an acropora.

[davidryder]

Wow eductors are something I've never even considered - thanks for the awesome idea

[liveforphysics]

Jonathan- If the output feels very directed an narrow the penductors aren't functioning very well.

From an energy perspective, the function of an eductor is to convert concentrated high pressure stream energy into low energy density large bulk flow. The outputs from my eductors is like a wide gentle river that carrys a VERY long way through the tank due to the large mass of the moving water.

If you would like Jonathan, tell me the specs of your application, and I will personally make you eductors to work for your setup and bring them over to you when I finally get the time to check out your awsome tank in person.

Best Wishes,
-Luke

[jnarowe]

well, in the first place, I am powering them with a Hammerhead, which is NOT a pressure rated pump. But what is coming out of them is very powerful narrow stream. Without them there is a lot of flow because the Hammerhead can move a good volume of water by itself, and this is really an experiment to bring my returns up higher in the water column and move the Vortechs lower.

Basic parameters are:

Hammerhead with approximately 4,100 gph after head loss going through the display. It supplies through a manifold the display on 4 x 1" lines, the multi-media reactor, and the fuge, which also gravity feeds into the display.

Post overflow most flow goes into the inbound sump but about 600 gph goes directly to the skimmer. The pickup line for the Hammerhead is 1.5" as well as the output to the manifold. The manifold is 1.5" with 1" spurs.

[liveforphysics]

Would you like the ends to be 1" FTP? 1" MPT?

I will make them to minimize the "laserbeam" effect you are currently getting with your penductors, and maximize the bulk flow rate.

BTW- Do you know or can you measure the orifice diameter on your current penductors please?

Best Wishes,
-Luke

[jnarowe]

The current Penductors are:

1 inch MPT Black Penductor with 0.375-inch orifice

The elbows I got are 1" FMPT, so the eductors should be MPT. The reason why I went with the Penductors is because they are black, and I wonder if I can't get you the appropriate black materials?

Although they are mostly hidden, it may be possible for them to be seen from the viewing pane. :)

[liveforphysics]

Well, I'm not going to play around trying to get black PVC, however, I will let you clean them and hit them with a coat of krylon fusion flat black :D

[jnarowe]

I can get the black PVC if you want. Have some already, but I am not sure what you would need. Wouldn't take very long to get either.

[yrema]

hats off to you, luke. this is one cool DIY! :)

[allstar.h2o]

Here is my thread you guys may find interesting. It is built right on 3/4 locline. Not trying to hijack your thread or anything, but somewhat similar design.

http://archive.reefcentral.com/forums/showthread.php?s=&threadid=1132785&highlight=eductor

[nrehman]

Live,
Great thread. Looking forward to building a couple of these.
Thanks.

BTW...any flow test results???