Eductor/Penductor Efficiency and Performance Data?

[rockskimmerflow]

Curious if anyone out there has any data figures for typical eductors used in aquariums to generate larger amounts of mass water movement. I can only find a very old advanced aquarist article that tested an eductor on a blueline branded panworld pump. The amount of net water movement increase seen in the test proved quite substantial without significantly increasing the velocity of the water.

http://www.advancedaquarist.com/2003/9/review

@Dana Riddle - I know you have done some seriously in depth testing of the tunze brand and other submersible flow type pumps and if anyone had any insight into how an eductor might stack up against these flow devices it would be you.

I ask because I am in the process of setting up a new coral propagation system of roughly 600g gallons consisting of 3 - 7'x3' 200g raceways. My current much smaller prop systems run with a continuous gyre type flow pattern generated by single tunze powerheads placed in 1 corner of the system. For the new propagation system I plan to run each of the 200g raceways on it's own panworld 100px-x return pump. I am hoping it is viable to plumb an eductor onto the end of each return line and run the systems with my preferred gyre pattern sans any submersible powerheads. If needed I will always be able to add a tunze or two into the systems. Hoping to be as efficient with materials as possible so I would prefer to use the return pumps which I have already selected to perform 2 tasks rather than just 1.

Seems like nobody runs eductors in home aquariums very often anymore so I guess I can understand the dearth of concrete info regarding their performance with different pumps of varying flows/pressure ratings.

Thanks in advance if anyone has info to share.

 

[Mark Gray]

Following I have not seen one of these for a long time

 

[Dana Riddle]

I tested two eductors individually coupled to a Little Giant pump (with a pressure gage plumbed in.) My curiosity was satisfied and I use one on my present tank. Unfortunately, this data has been misplaced (perhaps lost) in the flurry of activity when moving back to the mainland. Perhaps half of the research I do ever makes it to publication, but it is possible I can retrieve this info - I'll take a look. Short story - they work when coupled to a high volume pump and I like them and use one.

 

[rockskimmerflow]

I tested two eductors individually coupled to a Little Giant pump (with a pressure gage plumbed in.) My curiosity was satisfied and I use one on my present tank. Unfortunately, this data has been misplaced (perhaps lost) in the flurry of activity when moving back to the mainland. Perhaps half of the research I do ever makes it to publication, but it is possible I can retrieve this info - I'll take a look. Short story - they work when coupled to a high volume pump and I like them and use one.

Thanks for the info! Good to hear you've chosen to implement one on your current system. I guess there's nothing left for me to do but take the plunge. I'll hopefully be wet on the new prop system in a week or so. Will start with the eductors as the only flow and see how things look before I begin transferring livestock. I suspect the 100px-x pan worlds I'll be using to drive them will have plenty of grunt despite being the 'higher flow' versions of their pump line. The aquarium eductors I've seen tend to have a pretty large diameter venturi nozzle compared to the industrial ones I've seen with tiny 1/4" openings for use with very high pressure pumps so I hope I'll be ok with the relatively low pressure pan worlds I've chosen. Will report back when I've got an eye on how things are looking.

 

[Dana Riddle]

I'm using a Danner Mag 9.5 pump to run the educator on the return line. Its flow has pushed fine sand to one end of a 48" tank. Honestly, probably too much flow for a 90-gallon tank.

 

[greg 45]

Dont know if this will help or not. I have 3 tanks all the same size 8 foot long 4 foot wide 16 inches water depth .
Running a dolphin pump 6200 gph . Each tank has 2 eductors on the long end , on the other side in gyre mode 2 big 280's
Plenty of flow for sps. My only down fall is I have some tall rocks . If there were no rocks sps colonies would be rocking back and fort on the bottom of the tank .

 

[DCR]

I have used these type of eductors to mix storage tanks in my industrial career. According to the suppliers, they pull in about 3-5 times the motive fluid flow from the pump, but the pressure has to be very high (over 50 ft of head to get even the minimum value). For our aquarium installations , it is probably no more than 2 times the motive flow rate. Attached is a link to an industrial supplier. Although they certainly work, I don't think it is really cost effective to circulate water like this over using dedicated power heads except for relatively small tanks. You are avoiding the upfront cost of powerheads at the high cost of pumping power on the return pump.

https://eductors.net/tank-eductor/

 

[rockskimmerflow]

I'm using a Danner Mag 9.5 pump to run the educator on the return line. Its flow has pushed fine sand to one end of a 48" tank. Honestly, probably too much flow for a 90-gallon tank.

Wow that's very helpful anecdotal data. If a mag 9.5 is pushing sand at 48" through an eductor then I think I'll be well within range based on the pumps I'll be using. Being quite familiar with the Mag series and having swapped out a lot of Mag 12B pumps for the panworld 100px-x or even 50px-x in traditional locline style return setups, I can definitely say that the pan worlds have a bit of an edge on performance under back pressure. If you're getting that much flow in a 90 gallon I may even have some use for valving back the 100px-x's a bit since I imagine they'll have no trouble cranking a strong counterclockwise gyre with how I plan to implement them in the new 7 x 3 tanks. Many thx for your input Dana, I feel a lot better now about how the flow will look once I fire things up.

Dont know if this will help or not. I have 3 tanks all the same size 8 foot long 4 foot wide 16 inches water depth .
Running a dolphin pump 6200 gph . Each tank has 2 eductors on the long end , on the other side in gyre mode 2 big 280's
Plenty of flow for sps. My only down fall is I have some tall rocks . If there were no rocks sps colonies would be rocking back and fort on the bottom of the tank .

Woah that is a a serious setup. Are those displays or propagation tanks? I'd imagine without the rocks you wouldn't even need the maxspect pumps with the amount of throughput that Dolphin pump is generating.
I actually contemplated 2 - 8'x4' systems instead of the 3 - 7'x3' but lighting the 8'x4' would have proven a lot more tricky given my goals of material efficiency so I couldn't justify going with those larger footprint tanks. Thanks for the input I appreciate it. Feeling much more confident in the flow I'll be getting with just the eductors now.

I have used these type of eductors to mix storage tanks in my industrial career. According to the suppliers, they pull in about 3-5 times the motive fluid flow from the pump, but the pressure has to be very high (over 50 ft of head to get even the minimum value). For our aquarium installations , it is probably no more than 2 times the motive flow rate. Attached is a link to an industrial supplier. Although they certainly work, I don't think it is really cost effective to circulate water like this over using dedicated power heads except for relatively small tanks. You are avoiding the upfront cost of powerheads at the high cost of pumping power on the return pump.

https://eductors.net/tank-eductor/

Thanks for the link and your experience with industrial eductors. That type of data table was really all I've been able to find, but isn't very helpful or applicable to our aquarium based needs since those eductors are designed with the intent of being used on very high pressure per amount of volume output pump systems. I agree the wattage issue is a no brainer in favor of submersible propeller type powerheads if varied and well distributed flow is needed for a large display tank. In my case I will be using the pan world 100px-x pumps regardless so I figured making them do double duty is the best option. I've had great success already implementing purely laminar, horizontal gyre type flow patterns in shallow prop tanks without any rockwork. I've used tunze pumps to create this flow pattern in the past, but would like to be as efficient with materials as possible in the new tank array so I think if the eductor can increase the in-tank flow volume enough I'll be set. From what Dana and Greg have offered so far as far as anecdotal info I think I'll actually be right in the sweet spot with my pump selection and the eductors. Fingers crossed. Thanks for your input.

 

[Dana Riddle]

I tested two eductors. One - marketed for aquarium use - advertised an flow increase of 4x. I was skeptical, but after testing with an electronic flow meter (Marsh-McBirney FloMate 2000), I found the claim to be credible.

 

[greg 45]

rockskimmerflo / this system was built a few years ago . Each system only has one 400 watt metal halide reefbrite pendants on a light rail system going back and forth . Est. about 1 min side to side. I do have to than Dana Riddle he did help me out on this. The only light added after setting this up is four sections of 4 foot blue reef brite strips. There is good growth on the sps. After reading about the 65 k bulb I removed the radiums , I am not a fan of blue . The eye bulbs put out a heck of a punch. I am thinking of next trying a ultra sun 10k . There is a big skimmer and calcium reactor . Electric bill is around $300.00 a month .

 

[jda]

I only have anecdotes as well, but eductors with pressure/velocity pumps are no joke. These type of pumps are out of style for most smaller tanks, but they can be very effective on larger stuff and you see some on some CLs on larger tanks where even a MP60 or the largest Tunze are not effective.

FWIW - a Mag 12 without an eductor will push sand away from the glass about a foot on the other end of a 7' tank. With an eductor, it will push it back another foot and build a ramp of 8-10 inches, or more. It is too much flow.

 

[rockskimmerflow]

I only have anecdotes as well, but eductors with pressure/velocity pumps are no joke. These type of pumps are out of style for most smaller tanks, but they can be very effective on larger stuff and you see some on some CLs on larger tanks where even a MP60 or the largest Tunze are not effective.

FWIW - a Mag 12 without an eductor will push sand away from the glass about a foot on the other end of a 7' tank. With an eductor, it will push it back another foot and build a ramp of 8-10 inches, or more. It is too much flow.

Ok thanks that's quite helpful to know as well. The 100px-x pumps I will be using seem to be a bit stronger than the average Mag 12 I've run across. That sand moving flow at 7' must be through a single 1/2"? nozzle if the mag is pushing stuff around that far away. I have a couple Mag 12s in different tanks at full throttle through single 3/4" nozzles and while strong they aren't close to blowing sand that far away, but I can imagine with an eductor they would given how positive everyone's testimony has been.

Now you'll just have to put an eductor on the return line of your magic Laguna 2900 and see how much work it can do even with 16' of head pressure

 

[jda]

Just to clarify, I was referring to a Mag 12 in the tank as a powerhead, not as a return... wide open and full bore.

The Laguna is quite impressive, from the basement, it is not a power master. I shut down that tank anyway as I prepare to consolidate into a 900ish gallon new tank. It is too much power in a 44G brute mixing salt. It will get used again on the new tank, only with about 4' of head pressure.

 

[rockskimmerflow]

Just to clarify, I was referring to a Mag 12 in the tank as a powerhead, not as a return... wide open and full bore.

The Laguna is quite impressive, from the basement, it is not a power master. I shut down that tank anyway as I prepare to consolidate into a 900ish gallon new tank. It is too much power in a 44G brute mixing salt. It will get used again on the new tank, only with about 4' of head pressure.

Ahh that makes a lot more sense regarding the mag 12 being used as an in tank powerhead.

900 gallons is a serious tank, you going all halide on that sucker or a hybrid system?

 

[rockskimmerflow]

Update: Thanks for everyone's input here. Tanks are running and boy, oh boy was I underestimating how much flow this setup would generate. Ended up only putting in 2 of the 7' raceways instead of 3 because I don't need the extra space at this location yet and can definitely used the spare raceway elsewhere currently. That said, the 100px-x pumps are way overmatched for what I needed. I ended going with an asymmetrical pumping set up using one 50px-x running a raceway at 90 percent throttle- which creates the perfect amount of gyre flow for my needs- and I left one original 100px-x running the other raceway, but went ahead and T'd it off to run the UV and GFO reactor. Even driving those extra components I still have to keep it at no more than 80 percent throttle or it puts out way too much flow into the tank.

I'd never had a 100px-x and a 50px-x running side by side on the same system before so it was interesting to see the differences in how they perform. The 50px-x hates head pressure in comparison to the 100. Really takes a hit in flow as soon as I start backing the ball valve down further than 90 percent open. The 100px-x on the other hand hardly even registers a noticeable flow drop until I'm close to halfway throttled back on the valve. At wide open on both pumps, though, the flow only favors the 100 slightly. It's only when the simulated head pressure is added that you can start to see where the extra 40 watts the 100px-x pulls are coming into play. Interestingly, wide open under about 3 foot of head and being fed by a 2 inch manifold, the 100px-x audibly cavitates in the volute until the ball valve is throttled back 10 percent or more. I suspect this is because the pump is actually designed to see some moderate back pressure when running at its most efficient operating range.

 

[ca1ore]

My suspicion is that the use of a pressure pump is required to get the most out of these things. I tried panworld and Vectra pumps on my closed loop. While it is difficult to accurately gauge flow increases, my 'feel test' suggested to me that there was a significant flow increase when I used the panworld pump with the educator, but less so with the Vectra; though the latter moves more water when unconstrained by back pressure. Since I prefer to use the Vectra, it's mostly a push, though I do like the chaotic flow of the VCA nozzles so I use them.

 

[ca1ore]

I'd never had a 100px-x and a 50px-x running side by side on the same system before so it was interesting to see the differences in how they perform. The 50px-x hates head pressure in comparison to the 100. Really takes a hit in flow as soon as I start backing the ball valve down further than 90 percent open. The 100px-x on the other hand hardly even registers a noticeable flow drop until I'm close to halfway throttled back on the valve. At wide open on both pumps, though, the flow only favors the 100 slightly. It's only when the simulated head pressure is added that you can start to see where the extra 40 watts the 100px-x pulls are coming into play. Interestingly, wide open under about 3 foot of head and being fed by a 2 inch manifold, the 100px-x audibly cavitates in the volute until the ball valve is throttled back 10 percent or more. I suspect this is because the pump is actually designed to see some moderate back pressure when running at its most efficient operating range.

Just out of curiosity, do you mean the 100PX or the 100PX-X? The former is designed for pressure, the latter for flow. When looking at the specs (because I was debating between the 50PX-X and the 100PX-X for my chiller) it seemed that there was very little performance difference and the flow curves quite similar.

 

[rockskimmerflow]

Just out of curiosity, do you mean the 100PX or the 100PX-X? The former is designed for pressure, the latter for flow. When looking at the specs (because I was debating between the 50PX-X and the 100PX-X for my chiller) it seemed that there was very little performance difference and the flow curves quite similar.

Yeah the naming is kinda confusing, but I meant what I typed, the 100px-x. I'm fairly well versed on the hobby sized pan world and iwaki ranges since they are my go to externals. I don't use the 100px generally since it is most efficient for lower overall flow and higher head pressure applications. The 100px-x has way more than enough guts to run a single eductor. And in fact the 50px-x is about perfect with one on a 7' system as the sole source of flow I am finding. The 100px-x needs throttling to not overwhelm the tank with too much flow through the eductor.

For a chiller the 50px-x is likely a more efficient option since I imagine it's not running against much back pressure -depending on your setup of course. I use a ton of these 'higher flow' pan worlds on customer tanks since most systems realistically only present 7-8' of head at most. I've noticed the 100px-x does a lot better under more head despite it only having the same 'max head' as the 50px-x, but I'd never run them side by side on separate tanks. So I really got a good idea of the differences in their flow characteristics by playing with the kill a watt meter and the ball valves used to throttle them. It seems that at wide open with little plumbing back pressure the flow between the two pumps is nearly equivalent, but as soon as I started edging the ball valve past 10% or so of throttling back the 50px-x takes a nosedive. The 100px-x keeps on driving til I've got the thing at almost 50% throttled.

I now understand pan world's engineering between the two pumps despite their similar specs and flow curves. If you plan to run the pump in any decent amount of head (beyond about 5-6' I'd guess) the 100px-x really becomes the proper choice. But at very low head with little piping restrictions the 50px-x does nearly the same flow for 40 less watts. Both really excellent pumps IMO.

I almost went with a single 200PS I had lying around to run this raceway setup, but I'm glad I chose the 2 smaller pumps because I've got a lot more flexibility now as well as a savings of about 50 watts continuous draw. I do think the single 200PS would smoke both of these pumps in terms of raw pressure through the eductors. But that of course would come with that 50 watt or so penalty.

Edit: Curious as to why you prefer the Vectra? Controllability for the closed loop? I can understand that certainly. As far as reliability, longevity, simplicity/ few potential points of failure, and cost I would say the pan world runs away with it in my mind.

 

[ca1ore]

That's interesting. I'm a long time PanWorld user as well. I'm running the 200PS as my main return pump against 14 feet of total head and it is a beast. My skimmer uses the 100PX and my chiller the 50PX-X. CaRx and manifold both use the 20PX . My backup main is the 150PS. Gots me almost the whole PW family LOL. Really superb pumps and highly reliable. Been running a couple of them for more than a decade. My only premature failure was with the smallest 10PX, and is suspect that was more user error as I was asking it to do too much.

I use the Vectra on my closed loop because it's the sole pump in the stand and I want silent; plus the variable ramping works really well in that application. Even through the educators, it does well enough.

 

[rockskimmerflow]

That's interesting. I'm a long time PanWorld user as well. I'm running the 200PS as my main return pump against 14 feet of total head and it is a beast. My skimmer uses the 100PX and my chiller the 50PX-X. CaRx and manifold both use the 20PX . My backup main is the 150PS. Gots me almost the whole PW family LOL. Really superb pumps and highly reliable. Been running a couple of them for more than a decade. My only premature failure was with the smallest 10PX, and is suspect that was more user error as I was asking it to do too much.

I use the Vectra on my closed loop because it's the sole pump in the stand and I want silent; plus the variable ramping works really well in that application. Even through the educators, it does well enough.

Ahh gotcha. You really do have a fleet of pan worlds haha. I guess as a closed loop pump the Vectra isn't being tasked with reliability as a mission critical characteristic so the quietness priority definitely makes sense. The 200PS is indeed a monster. I have a couple clients who desire no powerheads in the tank whatsoever and I can say that running through 2 -3/4" round locline nozzles the 200PS generates pretty insane water velocity. I think the only Pan world pump I have never dealt with directly is the 250PS because there really isn't any point to implementing one over the 200PS unless we're talking about 30+ feet of vertical head in a given application - of which I don't have any. I do run a number of tanks with the good old 150PS because it seems to be a lot quieter than the 200PS and still pushes really good pressure through a couple 1/2" nozzles. Just not a flow monster by any stretch- at low head the 100px-x outflows it, but once there's some significant backpressure it comes into its own. I also just like the 150PS for more rugged applications since the impeller assembly is just so freaking robust on the PS series compared to the px line.