mjmods VS. Koralia

[jacmyoung]

<a href=showthread.php?s=&postid=9966534#post9966534 target=_blank>Originally posted</a> by jmkins
Its not just the gph out of the pump but the distribution and velocity profile. With my mods, albeit they were basic, the flow was concentrated at the small opening. The result was a very laminar flow that I had to bounce off the wall or else it would kill everything in its path. The K4 I have produces a very broad cone that travels the 3 ft of my tank in a turbulent pattern.

I still intend to keep a mjmod blowing detritus off the lower level of my tank after I pick up a second K4 but for overall random flow I like the K4 more.

I proposed this test when the maximods were young and never heard an answer; put two 20+ gallon garbage cans stacked on top of each other offset enough for the top can to hold a pump that empties into the first. Fill the top can with water and the pump output drilled and sealed into the bottom of the can. Put a scale underneath the bottom can. Fill the top can with water (weigh if possible) and plug the pump in. Measure the amount of time it takes to empty the top can. Weigh the remaining water in the top. Weigh the bottom can. Calculate the bottom cans water weight. Calculate the weight divide by the time it takes to fill and repeat the experiment several times.

I personally dont believe in bag tests, where a small volume of water is measured. There is too much room for error with these tests. I'm not trying to downplay the mjmods, if I upgrade I will put these in my tank. I just would like to see a more realistic experiment in terms of gph.

Of course for the same flow if the area of the flow is three times bigger, the velocity of the stream is only 1/3.

I used a 20g bag for my test, go to that Tunze Nano Mod thread and read my description and see if you think it made sense or not. I don't mean it is precision test at all, just estimate, but at least I have one you can look at and critique if you want to.

 

[jmkins]

<a href=showthread.php?s=&postid=9966140#post9966140 target=_blank>Originally posted</a> by jacmyoung
The reason the K4 is more forgiving is because they designed a bigger intake, a bigger motor and cavity and put a small prop and magnet driver in it. These are actually mentioned by Hydor as selling points I believe. The downside of it is of course for 1200 gph the pump appears bigger than it needs to be and draws more power (12W) than it has to be. The Tunze nano 6025 for example can pump 1250 gph (after simple mods) while drawing 7W and at almost half the size, but it does require more cleaning.

I dont mind the size of the k4 if it means that I wont have to clean as often. I would like to be lazy and cut corners when I can.

While your skeptical of the flow on the mjmods I'm skeptical of the flow on the tunze nano mods. The bag test is not very convincing as a gallon bag would fill in less than 3 seconds. There is too much human error in hitting a stopwatch in that amount of time. There needs to be larger volume tests that last several seconds or minutes for me to believe that these flow rates are real.

 

[jacmyoung]

<a href=showthread.php?s=&postid=9966578#post9966578 target=_blank>Originally posted</a> by jmkins
I dont mind the size of the k4 if it means that I wont have to clean as often. I would like to be lazy and cut corners when I can.

While your skeptical of the flow on the mjmods I'm skeptical of the flow on the tunze nano mods. The bag test is not very convincing as a gallon bag would fill in less than 3 seconds. There is too much human error in hitting a stopwatch in that amount of time. There needs to be larger volume tests that last several seconds or minutes for me to believe that these flow rates are real.

20g bag my dear, not one gallon. And BTW the results agreed with a 5g bucket test method, and also Roger at Tunze has just confirmed their own spec sheet were off and our tests were correct in pointing out those specs were off.

Again I am not talking pinpoint accuracy, but a good measure nevertheless.

 

[jmkins]

<a href=showthread.php?s=&postid=9966565#post9966565 target=_blank>Originally posted</a> by jacmyoung
Of course for the same flow if the area of the flow is three times bigger, the velocity of the stream is only 1/3.

I used a 20g bag for my test, go to that Tunze Nano Mod thread and read my description and see if you think it made sense or not. I don't mean it is precision test at all, just estimate, but at least I have one you can look at and critique if you want to.

I dont know a whole lot about fluid dynamics, but there are a few fundamental considerations for mjmods (and to an extent nanos) that pop into my head.

There is a sudden enlargment at the exit point of the mjmods which reduces velocity and increases pressure. Eddy currents produces a large current loss at this boundary reducing the velocity of the outgoing flow. These are classic calculation examples of bernoulli and continuum theory.

I cant say that the area is directly proportional in this situation given frictional wall forces or head pressure. I think that in most in tank situations that the head pressure is not equivalent to that of a small volume bag test.

In your 20 gallon bag test did you use mass and weight as variables? I would like to see how well the two correlate minimizing variability.

 

[jacmyoung]

What about the above real MJMod reading: 2000 gph at 19W, are you skeptical of that? Do you still rather believe 2000 gph at 12W? or 3000 gph at 12W?

You don't even have to get too smart at my nano tests, we are afterall talking MJMods claims here.

 

[jmkins]

<a href=showthread.php?s=&postid=9966695#post9966695 target=_blank>Originally posted</a> by jacmyoung
20g bag my dear, not one gallon.

wow that was derogatory.

I have a considerable amount of knowledge in fluid dynamics. I am just trying to promote an honest experimentally realistic value that the average hobbyist can reproduce with minimal equipment without an agenda.

So anyhow, any other industry would provide simulations of the flow output, especially given how easy it would be. If you cant see how flawed a 20 gallon bag with no head loss would be you cant be tossing out numbers on gph of modded pumps. :eek2:

 

[bergzy]

here are pics showing a magnet mount rotatable mjmod vs a nano stream vs a koralia 4 (sorry, k4 partially hidden).

hey, i just noticed an old nozzle modded mj1200 in the background. that sucker has been there on my wavemaker since i started the tank!!!

 

[jmkins]

<a href=showthread.php?s=&postid=9966751#post9966751 target=_blank>Originally posted</a> by jacmyoung
What about the above real MJMod reading: 2000 gph at 19W, are you skeptical of that? Do you still rather believe 2000 gph at 12W? or 3000 gph at 12W?

You don't even have to get too smart at my nano tests, we are afterall talking MJMods claims here.

I'm skeptical of both. If you read my reply you would see that. Your values are just as optimistic as those of the mjmods. Until you can provide a better, more realistic test you cannot argue their numbers. Yours are based on the same. I have seen a variety of power draws on different props, and different mj powerheads.

I personally dont believe any of those numbers, for mjmods or nano mods. If you look back at your prior posts it would make sense that pushing more gph would produce larger power draws, for both types of pumps right? Would it not make sense that the pump capable of the larger power draw (mj1200) could produce a higher theoretical flow?

As I've said in previous posts, the type of flow is very different in the mjmods versus the koralias. The koralias have a flow pattern that I have not seen in any other powerhead, most powerheads (stream pumps) are focused while the koralia is very dispersed. That is the major selling point for me, my own personal opinion. But I would like to see more sophisticated flow data generated for the mods on the other pumps before I would consider buying any of them.

 

[jmkins]

bergzy

how many degrees of freedom does the mjmod have compared to the nano or the koralia?

 

[dhnguyen]

For the record the flow rate of the mj mods have been tested by me and many others several times already. We all use the same method to test this similar to Tunze. Which is to say you attach a container (inflatable bag) infront of the shroud, turn on the pump and timed for some seconds. Then measure how much water is in the bag and the rest is just basic math.

This is not an easy test to do by yourself as the bag fills up rather quickly if you don't the pump off in time. Not only that but this test method introduce quite a bit of head pressure as well.

Unfortunately we don't have a more scientific way to test the flow rate and the best anyone could do is take an average from the test results. Conservatively speaking the large flow mod (MJ1200 w/ 1.75" Dumas prop) is estimated at 2000gph.

The only thing I personally haven't tested is the power draw.


D.

 

[dhnguyen]

<a href=showthread.php?s=&postid=9966810#post9966810 target=_blank>Originally posted</a> by jmkins
bergzy

how many degrees of freedom does the mjmod have compared to the nano or the koralia?

I can easily mount MJ mods on sea swirl, wavysea, or swirler-stein. Can't do that with nano or koralia.

Want to mount it using magnets instead? No problems. A couple of these will hold easily.
http://www.kjmagnetics.com/proddetail.asp?prod=BX0X06BR

The beauty with how I do my mj mod is that nothing is permanent and you can change and adapt as you see fit. Too much flow? Just swap out the propeller for a smaller one. Want a wider more dispursed flow pattern? Swap out the shroud for a larger one.

In a bind and need a quick a mixing pump? Just take the propeller off and put the original impeller back on and voila!

Enough freedom for ya?

 

[bergzy]

<a href=showthread.php?s=&postid=9966810#post9966810 target=_blank>Originally posted</a> by jmkins
bergzy

how many degrees of freedom does the mjmod have compared to the nano or the koralia?

sorry jmkins,

i pulled the mjmod pic off their website.

i dont have any mjmods and i am not willing to put in the time that is required to piece a mjmod together. plus, on a personal note, though i dont have any problems with ph's in the tank (i dont like closed loops), i refuse to have rough looking diy in my main display. this would be distracting to me as well as cheapening (again, my opinion) the overall look of the display.

i am not a fan of full size tunze streams as well as they are gargantuan to my eyes. yes, i do have inconsistent quirks do i not?

though the magnet for the koralia is larger than the nano's, they are smaller than a regular sized stream. this makes the outside of the tank not as 'cluttered'.

the koralia definitely has lesser degrees of adjustment than that of the nano. the k4 'pin' that is attached to the suction cup magnet binds at about 45 degrees (not going to reach in and move it since i finally got it 'just' right).

the nano has almost universal directional adjustment capabilities...with only the power cord getting in the way.

if i have time and feel a little diy adventurous, i might try and mount a nano on a wavy sea.

but what i am really waiting for is a directionally adjustable vortech...still waiting...still waiting.:rolleye1: :rolleye1: :rolleye1:

 

[jmkins]

<a href=showthread.php?s=&postid=9966813#post9966813 target=_blank>Originally posted</a> by dhnguyen
For the record the flow rate of the mj mods have been tested by me and many others several times already. We all use the same method to test this similar to Tunze. Which is to say you attach a container (inflatable bag) infront of the shroud, turn on the pump and timed for some seconds. Then measure how much water is in the bag and the rest is just basic math.

This is not an easy test to do by yourself as the bag fills up rather quickly if you don't the pump off in time. Not only that but this test method introduce quite a bit of head pressure as well.

Unfortunately we don't have a more scientific way to test the flow rate and the best anyone could do is take an average from the test results.

These tests are very easy to model with ANSYS, or similar fluid dynamic modeling programs. Experimentally the test that I proposed earlier would not be difficult, and could be done with tap water to provide more realistic estimations of flow than such small volume experiments. 20 gallon would be believable if the bag was weighed instead of just estimated by volume. This would be difficult since bags deform. A fixed volume container that was tared on a scale would reduce experimental error (which all of these flow tests are riddled with).

Until I see that very simple and repeatable experiment pulled off you guys are just pulling numbers out of no where. It is easy to round up or down when the times of experiments are seconds or fractions of seconds, that doesn't make those numbers accurate.

 

[jacmyoung]

<a href=showthread.php?s=&postid=9966763#post9966763 target=_blank>Originally posted</a> by jmkins
wow that was derogatory.

I have a considerable amount of knowledge in fluid dynamics. I am just trying to promote an honest experimentally realistic value that the average hobbyist can reproduce with minimal equipment without an agenda.

So anyhow, any other industry would provide simulations of the flow output, especially given how easy it would be. If you cant see how flawed a 20 gallon bag with no head loss would be you cant be tossing out numbers on gph of modded pumps. :eek2:

But for your peace of mind, let me describe my test:

I used a very sturdy 18g white garbage bag from Costco, and a 50g tub about 3x4x4' tall. I filled the tub with 30g of water, then started to fill the bag in the tub with my 5g refill bottle until 20g was poured in the bag, at that time the bag sit in the test tub and water line is full.

I then emptied the bag into the tub, cut a hole on the bag about 10" from the top, put my pump nozzle through the hole and taped them water tight with electric tape, installed the pump 2" below the water line while the empty bag floated on the water surface.

Then the pump was turned on and while water was pumped into the bag the bag gradually sinked into the tub until it was full right at the 20g mark. It closely resambled actual in-tank operation unless you have a hard time visualize it.

And there is NO head pressure with my test, it works just as if the pump is running in the tank.

I had a theory to help people easily estimate a prop pump flow when the flow is around 2000 gph, just multiply the watts by 100. Now I have one MJMod above to support that method of rough estimation: 2000 gph at 19W.

The others I have tested: a modded K4 doing 1700 gph at right around 17W, a modded 6055 doing 1900 gph at 20W and so on.

When the props are smaller, gph/watt increases, that is why you can get 1200gph at 7W (6025), or 500 gph at 3.5W (K1).

When the pumps are bigger it is the opposite, the gph/watt goes down, that is why you have the VorTech doing 3000 gph at 35W and Tunze 6100 doing 3200 gph at 45W. Of course with these large DC pumps some minor watt draw is attributed to the separate AC/DC transformers, how efficient these transformers are makes some difference.

 

[dhnguyen]

jmkins - please by all means do your tests. I would love to see the results one way or another.

I don't have access to any fluid dynamic modeling programs nor any scientific test facility to do this. Don't forget tap water has a much different property than saltwater and that will affect fluid dyanmic as well. No other pump manufacturers I know have done any real scientific flow tests on their pumps either. So I guess we are all pulling numbers out of nowhere.


D.

 

[jmkins]

<a href=showthread.php?s=&postid=9966842#post9966842 target=_blank>Originally posted</a> by dhnguyen
I can easily mount MJ mods on sea swirl, wavysea, or swirler-stein. Can't do that with nano or koralia.

Want to mount it using magnets instead? No problems. A couple of these will hold easily.
http://www.kjmagnetics.com/proddetail.asp?prod=BX0X06BR

The beauty with how I do my mj mod is that nothing is permanent and you can change and adapt as you see fit. Too much flow? Just swap out the propeller for a smaller one. Want a wider more dispursed flow pattern? Swap out the shroud for a larger one.

In a bind and need a quick a mixing pump? Just take the propeller off and put the original impeller back on and voila!

Enough freedom for ya?

No it isn't. My k4 can be rotated with 3 degrees of freedom to reach several angles that my mjmod cannot. The most sophisticated mjmod mounts that I've seen offer 2 dimensional at very most 180 degree motion, realistically it is much less, more like 120 degree rotation in a single plane. The magnet mount of my K4 gives me much more, and easier, mounting options out of the box. By the time I buy a mj powerhead, the diy pieces, and the mount I'm at the same price as the koralia or the nanos. On top of that both the Koralias and nanos have customer support for their pumps which marineland does not.

I cant see going the mjmod route given the options available right now. Hydor is coming out with a controller, and seio is coming out with the polario. The mjmod isn't economically viable at this point. If you guys have mounts that are as versatile as the hydors or nanos without costing more please post them. This has been the lacking variable in mjmods compared to the commercial counterparts.

 

[jacmyoung]

<a href=showthread.php?s=&postid=9966891#post9966891 target=_blank>Originally posted</a> by dhnguyen
jmkins - please by all means do your tests. I would love to see the results one way or another.

I don't have access to any fluid dynamic modeling programs nor any scientific test facility to do this. Don't forget tap water has a much different property than saltwater and that will affect fluid dyanmic as well. No other pump manufacturers I know have done any real scientific flow tests on their pumps either. So I guess we are all pulling numbers out of nowhere.


D.

I did notice when the same pumps were put in the reef tank, they tended to draw a watt more than in the freshwater test tub. The saltwater is a bit more viscous but the difference is within margin of error IMO.

 

[dhnguyen]

Ah but you forget... The whole point to MJ mod is not to go buy a new MJ and then mod it. This mod was intended for people who already own pumps like MJs and the likes to cheaply increase the flow in their tanks. Most of us have at least a few of these pumps lying aorund at one point or another.

I plan to build another swirler-stein (DIY sea swirl) to mount my MJ mods in the 125g setup I am slowly putting together. That will be more versatile and provide better random flow than anything the koralia or nano mounts can do.

 

[jacmyoung]

<a href=showthread.php?s=&postid=9966933#post9966933 target=_blank>Originally posted</a> by dhnguyen
Ah but you forget... The whole point to MJ mod is not to go buy a new MJ and then mod it. This mod was intended for people who already own pumps like MJs and the likes to cheaply increase the flow in their tanks. Most of us have at least a few of these pumps lying aorund at one point or another.

I plan to build another swirler-stein (DIY sea swirl) to mount my MJ mods in the 125g setup I am slowly putting together. That will be more versatile and provide better random flow than anything the koralia or nano mounts can do.

And people have been putting K4s and 6025s on seaswir for quite some time by now.

Your point of DIY spirit and pump reuse is valid of course, but I suspect this was not what the original poster had asked for, nor were our heated exchnages I admit.

 

[jmkins]

<a href=showthread.php?s=&postid=9966891#post9966891 target=_blank>Originally posted</a> by dhnguyen
jmkins - please by all means do your tests. I would love to see the results one way or another.

I don't have access to any fluid dynamic modeling programs nor any scientific test facility to do this. Don't forget tap water has a much different property than saltwater and that will affect fluid dyanmic as well. No other pump manufacturers I know have done any real scientific flow tests on their pumps either. So I guess we are all pulling numbers out of nowhere.


D.

D

PM me with your measurements on your best mjmods, and if you can the numbers on the mjmod kits. There should be very little differences between tap and saltwater measurements at these values, though I will do the best I can to approximate them. If anyone has cad drawings of mjmods, or other pumps, please pm me to make this even easier.

I'm not saying that you guys are pulling numbers out of no where, but the test that I proposed are very simple. Almost to simple for anyone who is going to mass produce and claim a specific flow rate. If I were to produce a pump and put a gph value to it I would at the very least use a flow meter, and not estimate (extrapolate) flow rates from a smaller pump. I would also put out potential velocity profiles in different size tanks. This is very basic information that anyone with an ME or ChemE background should be able to figure out in under 40 hrs. I will say that modeling the k4 is tougher since the output is wider with more openings, and the input is so open.