Dave W's 3000 gal plankton/reef tank

[Integral9]

I scrolled through the document and am overwhelmed by the number of choices and the technical details.

many of the options are very complex, but the double action piston pumps might be what you need. low speed and you can move a large volume of water fairly quickly. A low speed electric motor driving a wheel attached to the piston would work; like a steam engine. the rest is just check valves and plumbing.

[Chad]

Dave,

 

Please don't take this negatively, but it seems that your design goals (plankton friendly, large system, high turnover) are not mainstream goals. Which means that finding off the shelf items to meet your needs is going to be excruciatingly difficult or impossible. Some of the DIY ideas being thrown around may be precisely what will meet your unique needs. None of them are going to be easy, but dismissing them as "overwhelming," "daunting," or "over the head" may cause you to miss the thing that will work best for you. Delve into the details of the new idea with an open mind, force the understanding, and then apply the concept to your system.

 

What you are doing has the potential to be awesome, and there are a lot of folks here who are willing to help with the details, designing and building.

 

I apologize if you receive this message negatively. That is not my intention at all.

 

Chad

[dave w]

Dave,

 

Please don't take this negatively, but it seems that your design goals (plankton friendly, large system, high turnover) are not mainstream goals. Which means that finding off the shelf items to meet your needs is going to be excruciatingly difficult or impossible. Some of the DIY ideas being thrown around may be precisely what will meet your unique needs. None of them are going to be easy, but dismissing them as "overwhelming," "daunting," or "over the head" may cause you to miss the thing that will work best for you. Delve into the details of the new idea with an open mind, force the understanding, and then apply the concept to your system.

 

What you are doing has the potential to be awesome, and there are a lot of folks here who are willing to help with the details, designing and building.

 

I apologize if you receive this message negatively. That is not my intention at all.

 

Chad

Chad, I don't take your message as anything but constructive. I agree that moving large volumes of water slowly is out of line with the pump industry. I have a background in construction but not mechanics, so I need guidance and patience on mechanical ideas. I hope my descriptions of "overwhelming, etc." don't discourage anyone from explaining them further to me or making new suggestions. I hope you understand that what you see from me is owed more to my limited imagination than dismissal.

 

So keep up the creativity and I'll try to keep up with you.

 

On another note, I finished a google sketchup plan of the tank and water circulation patterns. I saved it in my pics, but for some reason my gallery here won't upload it. Can anyone help me in moving this image onto this thread? Thanks in advance.

[dave w]

many of the options are very complex, but the double action piston pumps might be what you need. low speed and you can move a large volume of water fairly quickly. A low speed electric motor driving a wheel attached to the piston would work; like a steam engine. the rest is just check valves and plumbing.

 

Thanks for pointing me toward a design, I got lost in the variety of choices they offerred. So how do I find a piston (and maybe piston ring) that is saltwater safe?

[Chad]

Dave,

 

I was hoping you would say something like that! I was afraid that this may be one those "give me a bunch of ideas, but I am going to do what I originally planned anyway" type of threads

 

You could make pistons out of laminated acrylic, virgin poly, or perhaps a couple of PVC discs attached to the ends of a pvc pipe for a dual "seal." Although, water piston pumps are pretty notoriously leaky, you could try to mount the piston vertically in tube that extends above the water line and ignore the leakage since it wont go anywhere that way.

 

On your upload issue, I always have to open my pictures in MS paint and "save as" then save as a jpeg to get them to upload. It also significantly reduces the size.

Edited November 7, 2010 by Chad

[Jon Lazar]

Are you sure that a pump impeller really damages plankton? I know a lot of people have said this on various internet forums, but that doesn't make it true. I would consider making sure that this a real problem before you start a complicated engineering project to solve it.

[Chad]

Jon, I remember years ago, I sent a question to Anthony Calfo when he was doing support at wetwebmedia... I wonder if his response is still out there somewhere... I'll see if I can find it.

 

 

[Jon Lazar]

Don't get me wrong; I love a good puzzle like this. In fact I've been trying to figure out how to build an acrylic Archimedes screw, but can't quite make it work.

 

 

Jon, I remember years ago, I sent a question to Anthony Calfo when he was doing support at wetwebmedia... I wonder if his response is still out there somewhere... I'll see if I can find it.

[dave w]

Dave,

 

I was hoping you would say something like that! I was afraid that this may be one those "give me a bunch of ideas, but I am going to do what I originally planned anyway" type of threads

 

You could make pistons out of laminated acrylic, virgin poly, or perhaps a couple of PVC discs attached to the ends of a pvc pipe for a dual "seal." Although, water piston pumps are pretty notoriously leaky, you could try to mount the piston vertically in tube that extends above the water line and ignore the leakage since it wont go anywhere that way.

 

On your upload issue, I always have to open my pictures in MS paint and "save as" then save as a jpeg to get them to upload. It also significantly reduces the size.

 

I cann be hard headed and slow, a dangerous combination, so thanks for your patience. I admit that the 105 rpm motors were so appealing that I already got a bunch of them. But there are many ways to skin a cat, and there is room for several types of water circulation in a large tank. As better ways are found, I will change my plans, the motors weren't very expensive. Given the time needed to lay block, weld the stainless steel angle frame and then fiberglass the box, we have at least a month, maybe a lot more. These things always take more time than you think.

 

I don't know what you mean by a dual "seal". Please explain using small words. Mounting the piston over the tank will be no problem. I will try your idea to upload the picture in a jpeg format.

[Chad]

I also love a good puzzle like this... heh, and this particular puzzle is one that I have had many thoughts on. An archimedes screw would be awesome!! Doesnt IA have one in operation on their system?

 

Centrifugal pumps damaging plankton? 12/29/04

Dear WWM crew, First off I would like to say that I have literally spent hours perusing your forums, enough that my wife groans when she sees me on the computer

<glad to hear the former, not the latter... do take care of family first and foremost >

Thank you for offering a great service. I have heard from a few different places in passing (mostly magazines, and in a couple of places on the WWM pages) that our common centrifugal pumps are limiting our ability to maintain significant zoo and phyto plankton populations in our aquariums,

<actually, this is archaic information/belief based on some silly research with brine shrimp that was extrapolated to be applied to marine plankton. In truth, marine plankton act nothing like (salt lake) brine shrimp and suffer very little plankton shear. The point is also ultimately moot as the plankton come out just as edible on the other side If you were hungry, would you refuse a hamburger because you wanted a steak instead? <G>>

and thinking about it makes sense that the plankton could be damaged by colliding with the volute of the pump.

<you'd be amazed what commonly passes through... I have seen small fish make it numerous times>

Since I cannot seem to find anything more than speculation on this subject I was wondering what y'alls opinion is.

<it is only speculation and bunk at that. No worries on plankton shear>

Do you think there is any benefit in trying a reciprocating or perhaps rotary pump? I am thinking that the non-uniform output of the reciprocating pump could have its advantages (more turbulent flow etc.) but more complicated design would lead to more maintenance. I would love to hear the WWM opinion on this subject.

Thanks very much for your input Chad Miltenberger

<hamburger 'til it hurts, mate. Anthony>

[Chad]

How about a picture?

 

This is what I mean by double seal. Two plastic disc's capping each end of a center piece of pipe.

 

[dave w]

Are you sure that a pump impeller really damages plankton? I know a lot of people have said this on various internet forums, but that doesn't make it true. I would consider making sure that this a real problem before you start a complicated engineering project to solve it.

 

 

John, this could be correct, I don't have any personal evidence to back this up, just my intuition. Most plankters are soft bodied, and I don't think shearing by the impeller is the problem, its the "zero to 60" instant acceleration that gets them. To use a rough analogy, if the human body can only handle say 15 G's of force and you are subject to acceleration of 25 G's, all your organs get plastered like hamburger against your backbone and you will die without a mark on the outside of your body. Although this is a crude example, it is how I view 1720 rpm impeller pumps that typically have outlets of an inch or less.

 

Conversely, a 105 rpm motor has one sixteenth the speed of the typical pump and an 8" outlet has an area about 62.5 times greater than a 1" outlet (50 square inches versus 3/4") so the the slow system has about one thousanth's of the acceleration force (16 times 62.5) on plankton. I am probably a little off with my math, and I may certainly be wrong in my theory, but this is what I am operating under, somebody please let me know if I am crazy. I know a lot of manufacturers claim their product is plankton friendly, but if their water movers are high rpm with small outlets I think they're not accurate.

 

Please don't take this as a condemnation of high speed motors or anyone's system. These motors are the mainstay of the hobby for good reason -- they are reliable, cheap, and get the job done. I'm just trying to do a different type of job.

[Chad]

I also love a good puzzle like this... heh, and this particular puzzle is one that I have had many thoughts on. An archimedes screw would be awesome!! Doesnt IA have one in operation on their system?

 

Yep, they do.

 

[dave w]

How about a picture?

 

This is what I mean by double seal. Two plastic disc's capping each end of a center piece of pipe.

 

 

OK, now I see more of what you're talking about. Each disk on the end acts as a compression ring/seal, and the thingy in the center makes it all into a piston, right? So you put this inside the pipe and on either side of the contraption you put a check valve (in opposite directions). Am I getting close? Beautiful diagram by the way. I admire people with this kind of computer skill.

[Chad]

Yep, you got how it works.

 

Now, this could be done as a solid cylinder, but it would increase the friction (although probably reduce leakage somewhat - efficiency has to take its hit somewhere). Disadvantages of this type of a setup include higher probability of failure (check valves, piston seal if you are using one) and thus higher maintenance, and a somewhat complicated design.

 

Thanks, it isnt me, though, I was able to pick up an inexpensive copy of autocad through my alma mater, it is fast to work in and does nice renderings.

[dave w]

I also love a good puzzle like this... heh, and this particular puzzle is one that I have had many thoughts on. An archimedes screw would be awesome!! Doesnt IA have one in operation on their system?

 

 

I see the point, and have also seen many small critters go through a water pump to be alive on the other side. But in playing the odds, even if something advertised as a plankton friendly pump/powerhead only kills 1% of the plankton and the tank turned over 10 times an hour, wouldn't you achieve a 100% kill rate every 10 hours? I want tens of millions of planton to cycle through the system continually with near 100% survival so they can later be eaten live, not half dead. Until shown the error of my thinking, I hope my intuition is correct. I promise to change (reluctantly) when smarter people prove me wrong.

 

An Archimedes screw would be wonderful, but I can't find anyone who makes small ones. They make really big ones for sewage plants.

[Chad]

I never did quite completely buy it... I still dont. However, for me anyway, I stopped the pursuit after three things occured almost simultaneously. First, the time in my life was extremely busy and I didnt have the time to devote to it that I wish I would have had. Second, I noticed that my DIY skills would be pushed to their limits (meaning rework) and when version 1.0 didnt work, I didnt have money to try again. Third, I had a hard time defining the payoff for the effort (I wasnt trying to raise anything, I just wanted to replicate nature as much as I could). So it wasnt worth it for me, at that time.

 

Recently, I read a study somewhere that said calanoid copepods are mostly absent from captive systems because their antenae are damaged by impellors, which mortally wounds them. I think there is merit to what you are doing. Hopefully, it will be successful.

 

Maybe Jon will figure out his Archimedes screw out of acrylic. I would think it could be done on a capable CNC machine.

[dave w]

I never did quite completely buy it... I still dont. However, for me anyway, I stopped the pursuit after three things occured almost simultaneously. First, the time in my life was extremely busy and I didnt have the time to devote to it that I wish I would have had. Second, I noticed that my DIY skills would be pushed to their limits (meaning rework) and when version 1.0 didnt work, I didnt have money to try again. Third, I had a hard time defining the payoff for the effort (I wasnt trying to raise anything, I just wanted to replicate nature as much as I could). So it wasnt worth it for me, at that time.

 

Recently, I read a study somewhere that said calanoid copepods are mostly absent from captive systems because their antenae are damaged by impellors, which mortally wounds them. I think there is merit to what you are doing. Hopefully, it will be successful.

 

 

 

I have also studied that pods are fragile and need very gentle handling. Thanks for the reassurance. After several (even well meant) criticisms in a row, I start feeling a little insecure about my goals. But the bigger part of me wants the tough criticism. Its very cheap to make adjustments while building the systems, very expensive to fix things after the fact.

[Chad]

What's the difference if you were to make an array of 4) 2" cylinders with individual pistons but controlled by the same size motor as the bigger one? If you make an eccentric cam, then you could get 2 pairs of alternating surge pumps. Maybe a little more complex, but probably considerably cheaper than using the big pipe.

 

The difference is area. In my original guestimate, I threw out a 24" diameter tube. In order to move the same volume using 6" cylinders, you would need 16 of them. The complexity difference and friction difference (requiring a much larger pump because there is four times the surface area contributing to friction) that this adds probably makes it not worth trip even if 6" parts are more than 1/16 the cost of 24" diameter parts... which I dont think is accurate.

Edited November 7, 2010 by Chad

[dave w]

The difference is area. In my original guestimate, I threw out a 24" diameter tube. In order to move the same volume using 6" cylinders, you would need 16 of them. The complexity difference and friction difference (requiring a much larger pump because there is four times the surface area contributing to friction) that this adds probably makes it not worth trip even if 6" parts are more than 1/16 the cost of 24" diameter parts... which I dont think is accurate.

 

Now that I understand your concept, I begin to see how to make one. Given the high cost of large pipes, it may be easier to build the circle disks first, then wrap a fiberglass sheet into a circle around them for a 24" diameter or other pipe size. What serves as a flange between the disks and the pipe?

 

I am buying two rolls of premade 5 oz fiberglass (5' by 50') to glass the tank anyway and will have some left over. Can anyone tell whether a watt of power plunging the piston up and down will move more water than a watt of power turning a propeller? I just don't know enough about mechanics to hazard a guess.

[dave w]

Getting back to the surge device. One reason I'm reluctant to involve the sump on a 3,000 gallon tank is the electricity cost of lifting 24,000 pounds of water up 5' from the sump back to the tank. Far cheaper to circulate water inside the tank and use the sump to grow pods and artemia.

 

When I upload a sketch of the tank design it will show four large, shallow refugiums just above water level. My idea is to give them lots of flow in full sun, shallow sand and water depth, and be easily harvestable to feed 50 angelfish. An air driven geyser pump can lift lots of water this short vertical distance for the refugiums. But because geyser pumps use an air bubble to lift water up a wet tube, they can easily lift it higher than the few inches I have planned. Should I raise the refugiums and have them drain into a surge bucket? I like the concept of getting double use out of the water pumped through the fuge. What does everyone think?

 

Actually, if the surge devices contribute much to the in-tank circulation, it would be getting triple use out of the refugium flow.

Edited November 7, 2010 by dave w

[dave w]

 

My apologies for the low quality photo. I couldn't copy this from google sketchup to my gallery. Either there are proprietary limits by Google, or I am a computer idiot. I suspect the latter. So I did it the caveman way. I took a pic with my cellphone and emailed it to myself, then transferrd it to my gallery.

 

But one can see the four long green fuges above the water, the peninsular tank layout of five panes of glass (plus two end caps), and the downwelling tubes along the back wall for circulation via low rpm propellers. The horizontal square tubes indicate water outlets. I didn't know how to sketch these without the blockiness. If someone can help me walk through posting the sketch on google, anyone can then access the program and see it from different angles. The two round tubes coming out of the end caps indicate pipes that turn the horseshoe into a circular donut for more water flow. This is how I can simulate tides.

[Coral Hind]

It looks very nice. You probably mentioned it somewhere in this thread and missed it but what type and thickness of material are you using for the viewing panes?

 

You could hit the "print screen" button and paste that into Windows Paint, then save and post it.

[ctenophore]

I forgot to mention the piston idea when you were over at my place Dave. You won't need a 24" diameter piston. A 6" wide one will set your entire water volume moving. The trick is finding the resonant frequency to set up a standing wave. I can demonstrate on my 750 gallon tubs. I used a capped 2" PVC pipe inside a larger diameter pipe as a test, and within a few minutes of pumping it up and down by hand I was able to create a standing wave that sloshed water out of the tanks. It's even easier with e.g., a 6" dia. 1-gallon bucket. Building a piston drive exactly like Garratt's will cost about $200 in parts, assuming using 6" duct PVC for the cylinder and a custom cut inner piston. It will move ALL of the water in your tank. I would still use a few of the large props to circulate that water- the wave just moves the water back and forth over a small area, you still need some (but not a lot) of force to cause true circulation. Plan on keeping at least 6" of clearance to the rim of the tank if you go this route so as not to slosh water out with the piston.

 

Justin

[Chad]

Now that I understand your concept, I begin to see how to make one. Given the high cost of large pipes, it may be easier to build the circle disks first, then wrap a fiberglass sheet into a circle around them for a 24" diameter or other pipe size. What serves as a flange between the disks and the pipe?

 

I am buying two rolls of premade 5 oz fiberglass (5' by 50') to glass the tank anyway and will have some left over. Can anyone tell whether a watt of power plunging the piston up and down will move more water than a watt of power turning a propeller? I just don't know enough about mechanics to hazard a guess.

 

Your fiberglass idea is good, what about using a sonotube for the mold to wrap fiberglass around? It might by difficult to get it out after the glass cures, but it is an idea. The disc's will be easier to size than the diameter of the tube.

 

As far as the flange, I would think that seating the center "tube" in a groove and holding the whole thing together with a strongback that doubles as a mounting point for the piston rod, like this. Stainlss steel is an acceptable material.

 

 

and the back