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Mini-Eductor


bigJPDC

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Completed the build last night, after finally getting out to Lowes for the parts. Home Depot sucks.

 

I started with the threads on RC - http://www.reefcentral.com/forums/showthre...ghlight=eductor and quickly realized that this was way to big and heavy for my SeaSwirl return. So once I had the parts together I made some adjustments that made the overall length and weight less, but still allowing the jetting to work. After researching commercial eductors I thought the origional design was too long anyways.

 

IMGP0371.jpg

 

IMGP0370.jpg

 

Looks like a maxijet mod I have in a box somewhere. Yauger - yes I painted it black last night. :lol2:

 

Realistically, what I had before on the Sea Swirl was a 3/4" MT to 1" hosebarb fitting, so probably wasn't all that efficient, but - this think is awesome. My Neon GSP on the opposite side of the tank is standing stright up, and I see sand everywhere moving around. All without changing the flow volume.

 

I'll watch it later today when lighting comes on, and see just how conspicous this is but so far I am digging it.

 

jp

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(edited)

Looks like a maxijet mod I have in a box somewhere. Yauger - yes I painted it black last night. :lol2:

 

LOL dude I know I know I get it now... apparently its possible paint PVC and use it in your tank... dang why do I feel like the kid on the short bus today? LOL :wig:

 

thanks a cool DIY MOD, I might have to "borrow" your design....

 

:eek:

Edited by yauger
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Completed the build last night, after finally getting out to Lowes for the parts. Home Depot sucks.

 

I started with the threads on RC - http://www.reefcentral.com/forums/showthre...ghlight=eductor and quickly realized that this was way to big and heavy for my SeaSwirl return. So once I had the parts together I made some adjustments that made the overall length and weight less, but still allowing the jetting to work. After researching commercial eductors I thought the origional design was too long anyways.

 

IMGP0371.jpg

 

IMGP0370.jpg

 

Looks like a maxijet mod I have in a box somewhere. Yauger - yes I painted it black last night. :lol2:

 

Realistically, what I had before on the Sea Swirl was a 3/4" MT to 1" hosebarb fitting, so probably wasn't all that efficient, but - this think is awesome. My Neon GSP on the opposite side of the tank is standing stright up, and I see sand everywhere moving around. All without changing the flow volume.

 

I'll watch it later today when lighting comes on, and see just how conspicous this is but so far I am digging it.

 

jp

 

What the heck is an eductor?

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What the heck is an eductor?

 

:) http://www.nciweb.net/tank.htm

 

Basically, by shooting water past an opening, you draw that water in and along with it - hence the 'one gallon in, five gallons out'. It's kind of the same physics that makes some bubble silencing contraptions draw in air and makes things worse than before.

 

I am anti-powerhead, so this maximizes the flow in the tank while keeping the return dialed back. I have it attached to a SeaSwirl and did nothing other than replace the outlet. It's already dug out one corner about an inch.

 

IMGP0380.jpg

 

IMGP0384.jpg

 

jp

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Thats gotta suck in a ton of air that close to the surface... or am i missing something... and your rock stacking frightens me... what's the secret to keeping it from falling over

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Jason - it doesn't suck in any air, that's the beauty. I only see it moving water and the occasional large air bubble. My water is very clear now in fact, I think it is helping clear up the organics in my water by increasing the surface agitation.

The rocks have a big piece of plastic coat hanger running through them and have light pieces on top of a huge base - they aren't going anywhere.

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so this is a good idea for people such as myself who have 1 return from their sump to increase water movement?

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I'd say so - at least in my case it's blown away any other type of outlet I've seen - and for $5 in parts.

jp

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is that metal?? you painted it?? what kind of paint?

 

All plastic parts - check out the RC thread for the part numbers - everything is at Lowes in Dulles TC.

I paint everything black - like to use Rust Oleum plastic paint, but many also report success with Krylon Fusion.

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(edited)

Hey Big J

 

You have inspired me to try this out. I read the threads and then ignored them and made the design up myself. :drink:

 

572733471_3639f71b22.jpg

 

The main differences in mine are:

 

-1.25" coupling instead if 1.5"

-a couple creative part substitutions were required, despite trips to 3 different Home Depots

-I needed a "custom" adapter since the previous owner of my tank used slip bulkheads and then cut off the pvc inside next to a fitting so normal PVC sizes don't fit

-instead of screwing the hose barb in backwards I used a slip reducing bushing and dremeled out the lip inside so I could glue pvc in from both sides.

 

I can't say how much more flow it has given me, but I am definitely getting more surface agitation (then again I made the return nozzle 6" longer)

 

This guy is powered by a Mag 7 closed loop, and brush painted with 2 coats of Rustoleum latex paint. Spray paint would have been much easier but I had this on hand.

 

Works for me! Thanks J!

Edited by dchild
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NICE!! Awesome design - could you lose the coupler in between your 45 and the part with the holes in it? That's what I removed for my variation. That thing is right out of Marvin the Martian.

 

I think there was a post on that RC thread which mentioned that the eductor might not be as efficient on a closed loop.

 

Is latex paint safe?

 

 

jp

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ok so let me be stupid for a minute

 

is the way this thing works like what happens when a big truck flies 80mph down a dirt road? Going along its path, the force of movement pulling up the dirt or water as it passes?

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ok so let me be stupid for a minute

 

is the way this thing works like what happens when a big truck flies 80mph down a dirt road? Going along its path, the force of movement pulling up the dirt or water as it passes?

 

 

 

Yes. A low pressure zone is created at the openings on the side that draws additional water into the unit which is projected forward with original volume of water.

 

I just installed a eductor/penductor that I purchsed from Premium Aquatics for $25. It works great, increasing the volume of water that a pump pushes, however, it doesn't come with the same appeal and satisifaction of one that you made yourself.

 

penductor.jpg

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NICE!! Awesome design - could you lose the coupler in between your 45 and the part with the holes in it? That's what I removed for my variation. That thing is right out of Marvin the Martian.

 

I think there was a post on that RC thread which mentioned that the eductor might not be as efficient on a closed loop.

 

Is latex paint safe?

jp

 

Thanks! You pegged it, that coupling was one of the "I'm done driving to Home Depot" compromises. I may redo this and take the coupling out at some point in the future but for the moment I like the increased surface agitation. I have a 125 (6' long) and I have trouble getting adequate surface flow b/c it is plumbed as a room divider which means all the plumbing is on one end.

 

I didn't see that post, but I cannot imagine why whether or not it is a closed loop makes any difference. All the eductor sees is water flow; makes no difference where the pump is. If anything I'd think (in general) they'd work better on closed loops since the lack of head pressure will generally mean a closed loop gets more flow than the return.

 

Is latex paint safe? Well, my fish are still alive :) I have no knowledge of aquarium-specific usage but I believe once it dries it is functionally the same as spray paint. I've used it in stands and hoods forever with no ill effect. If I do have problems I will let everyone know.

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(edited)

Nice tank! The room divider leaves you somewhat boned in terms of plumbing though, but if it was me - I'd mock up an acrylic bracket for two SeaSwirls and hang them in the center of the tank, both with eductors of course. Stagger them and also their motion and you wouldn't need powerheads.

 

You could hide the plumbing and power cords in the hood, and several folks out here could help with the bracket fabrication.

 

jp

Edited by bigJPDC
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I tried to build the original eductor, but the parts are next to impossible to get in Maryland. IVGONMAD can get them in at Lowes in CA, but they don't stock the same parts in Maryland. Plumbing codes? Regional suppliers? I don't know, but that design really needed those exact parts. He even offered to send them to me after I sent him the Lowes page that said "not in Maryland."

 

I bought some of the small commercial eductors, but I haven't been able to measure whether they really move more water. They push sand in the far corners, but that might be because the stream is more focused than in my old 1" pipe outlet. I tried pumping from one bucket into another, holding the eductor just below the dropping waterline. That certainly didn't suggest 4x the flow.

 

http://www.kthsales.com/website/Misc/hello...enthusiasts.htm

 

Part of the issue may be that eductors work best with high pressure pumps, and we mostly use low pressure returns.

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For parts, I didn't even bother looking at the part numbers. A lot of the parts in the original thread are ABS (black) which are far less common. I recommend building from white PVC and painting. I wish I had taken pictures of the build process, maybe next time. Mine was built essentially from a 1 1/4" coupling and a bunch of reducing bushings; take a few minutes at Lowes/HD doing dry fitting to see what works for you.

 

An eductor will not work so well in a pump-between-buckets scenario. You want all the restriction (which causes back pressure) to be in the nozzle inside the eductor, not after the whole assembly. The eductor trades pressure/velocity for volume, and if you require pressure from it (i.e. through a hose between buckets) then you lose that benefit. From the threads on maxi-jet mods, the preferred flow-measurement method seems to be to hold a plastic bag of known size (say 3 gallons) underwater in front of the eductor and see how fast it fills up. The bigger the bag, the more accurate your estimate, but you need a pretty big space to use it. I say rinse the bag and perform the test in your tank.

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For parts, I didn't even bother looking at the part numbers. A lot of the parts in the original thread are ABS (black) which are far less common. I recommend building from white PVC and painting. I wish I had taken pictures of the build process, maybe next time. Mine was built essentially from a 1 1/4" coupling and a bunch of reducing bushings; take a few minutes at Lowes/HD doing dry fitting to see what works for you.

 

An eductor will not work so well in a pump-between-buckets scenario. You want all the restriction (which causes back pressure) to be in the nozzle inside the eductor, not after the whole assembly. The eductor trades pressure/velocity for volume, and if you require pressure from it (i.e. through a hose between buckets) then you lose that benefit. From the threads on maxi-jet mods, the preferred flow-measurement method seems to be to hold a plastic bag of known size (say 3 gallons) underwater in front of the eductor and see how fast it fills up. The bigger the bag, the more accurate your estimate, but you need a pretty big space to use it. I say rinse the bag and perform the test in your tank.

 

In the original thread, even the non-ABS parts weren't available around here. So if you could post an East Coast parts list, people might find that useful.

 

I did the test through the air between buckets so there was no restriction, but I then was asking it for pressure. :biggrin:

 

Did you do the bag test?

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In the original thread, even the non-ABS parts weren't available around here. So if you could post an East Coast parts list, people might find that useful.

 

I did the test through the air between buckets so there was no restriction, but I then was asking it for pressure. :biggrin:

 

Did you do the bag test?

 

For the bag test, I got 2.4x the flow using the Penductor pictured above. I had only gotten about 1.25x when trying to test using the bucket2bucket method I tried earlier.

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Every part from the RC thread was found at Lowes at Dulles Town Center.

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Every part from the RC thread was found at Lowes at Dulles Town Center.

 

According to Lowe's web site, the reducer coupling (25017) is now carried in VA and MD. It was mail-order only in the spring, but stocked locally in CA.

 

The specific barb adapter 194541 (and ivgonmad used a design feature of this specific adapter) is no longer carried by Lowes even in ivgonmad's Eastlake, CA store. If you buy one with a knurled barrel instead of with a molded nut, then you'll have to grind the knurls off to use it with ivgonmad's design.

 

Trying to build the original design I put a hundred miles on the car, a couple hours on the internet, and exchanged several PMs with ivgonmad. He offered to send me the parts from CA once I sent him the Lowes parts links :) , but it was past being cost-efficient or fun.

 

But DIY or COTS, eductors are cheaper than bigger pumps!

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  • 2 weeks later...

Great feedback here guys. I chopped down a coupler and lowered my eductor an inch or so under the water, so I now have a direct bead on some SPS I have in the center of the tank. I had to epoxy one milli frag down as it was getting blown out of its hole.

 

The periscope thing is hilarious as it moves back and forth on the SeaSwirl. I have cranked up my return now that the surface isn't as agitated and the fish love to swim in front of the eductor and ride the waves. Yeah it's somewhat obtrusive, but not any moreso than powerheads, maximods or locline is either IMHO.

There is a major dead spot immediately below and behind the eductor - the right thing to do here would be to have two of these at opposite ends, sides or corners of the tank, oscillating back and forth. My 3' tank is too small for two of them, but I could see that working for a 5-6' tank. No need for a SCWD or timer, the randomness of the SS, especially when their flows hit each other in the middle would provide that motion.

 

Now I just gotta finish my basement so I can build out that 4' cube and prove this works on a larger scale.

 

jp

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