Dave W's 3000 gal plankton/reef tank

[Chad]

Here is the you tube video... pretty freaking cool if you ask me.

 

Simon Garratt's piston wave maker

[Jon Lazar]

The Carlson surge device (or one of the many modifications) is a tried-and-true approach to creating surge, especially in a large tank.

[Coral Hind]

Actually I asked my brother about that one and he said aquariums are outside of the building and inspection codes.

 

Well that is a good one to know.

[Coral Hind]

The Carlson surge device (or one of the many modifications) is a tried-and-true approach to creating surge, especially in a large tank.

I like the Carlson device because it makes for larger, more dramatic waves and does a good job at aerating the water. It can create micro bubbles that some people dislike.

[dave w]

I was thinking of something more along the lines of a single chamber in the tank with a piece of acrylic in it that is mounted on one side on an axle. The other side is hooked up to piston (think of old steam locomotives) that drives it very slowly back and forth. This would basically just "stir" the water up. Essentially, it would be similar to tilting the tank back and forth as the water would be forced in one direction and then the other by the fin that moves back and forth. It's not much different than the concept of fanning yourself with something flat. The back and forth motion would push the water back and forth.

 

Have you thought of using a massive air pump in order to drive the water up? I know that some commercial applications use massive air pumps to move water, I'll bet you could do something like that, although it would probably be fairly noisy. I would think with the lack of spinning impellers or propellers you wouldn't lose much plankton from the system.

 

Davelin,

 

I have given that a little thought, but still don't know exactly what to do. I was thinking of mounting one of the slow turning motors on one of those motorized light rails and moving it through the tank. As I hope you can see, the horseshoe shaped tank has two curves and I don't think these light rails are made for curves. So my options are to get a light rails for each of the three sides, or be happy with one 20' rail on the long leg of the tank to stir things up. Putting a stationary paddle like you suggest would also do the trick. I have thought about large air blowers and even own a few, but they are somewhat noisy and in the winter they will cool the water a lot. In the summer they should do well. To run the geyser pumps I am thinking of using large diaphragm air pumps. They will displace a lot of water if I can keep down the sound of air exiting the top of the geyser pump chamber. It could be noisy.

[dave w]

Here is the you tube video... pretty freaking cool if you ask me.

 

Simon Garratt's piston wave maker

 

Chad, that is a very cool video. It looks like it displaces about a quart of water. In my case I need to turn over 3,000 gallons of tank up to 20 times per hour, so I think this is not a direction that works for my application. If I'm going to move 60,000 gallons an hour at slow speeds, I need large diameter propellers that keeps the G forces of acceleration within the soft bodied plankters ability to survive, so I've chosen motors that only turn at 105 rpm. The typical powerhead or pump turns at 1720 rpm.

 

 

Although the prop blades only turn at 105 rpm, their 8" size moves a tremendous volume of water at slower speeds. I think the same 60 watt motor in a powerhead or low rpm motor will move the same volume of water, but the slow motor has perhaps one thousandth the G force of a powerhead.

[dave w]

The Carlson surge device (or one of the many modifications) is a tried-and-true approach to creating surge, especially in a large tank.

 

Jon, I have looked into Carlsons in the past, but admit that I don't know a lot about them. They are a great way to create surge in a large tank. But how does the water pump up those several feet into the surge device? To keep a tank teeming with tens of millions of plankton, I can't fill the surge device by traditional means -- the 1720 rpm impeller pump which (in my opinion) kills 99% of plankton. If we can find a way to lift water several feet without using an impeller pump, we are in business.

[dave w]

I like the Carlson device because it makes for larger, more dramatic waves and does a good job at aerating the water. It can create micro bubbles that some people dislike.

 

Jon and others, please give me your opinion. Is it more important to have a surge device or in-tank water flow? While the ideal answer would be "both", with a tank this large I have to be mindful of my utility bill.

 

Lifting water requires more energy than simply circulating it. Let's suppose that filling a 50 gallon Carlson device at 2' of head in one minute requires 200 watts of pump power. That same 200 watts might drive a propeller at zero head to move 8,000 gph in the tank. I would like to do both, but I think the priority is to get 20x tank turnover on the fewest watts possible. I think using an air device to lift water into the surge device is a great idea, but I haven't figured out the mechanics. I'm not the best mechanical mind around.

 

Do people agree? Is it likely that the gravity of the water weight falling from the surge device will pull a lot of tank water along with it, and the 200 watts of surge power may circulate the same volume as a 200 watt powerhead. If so, count me in.

[Chad]

Chad, that is a very cool video. It looks like it displaces about a quart of water. In my case I need to turn over 3,000 gallons of tank up to 20 times per hour, so I think this is not a direction that works for my application. If I'm going to move 60,000 gallons an hour at slow speeds, I need large diameter propellers that keeps the G forces of acceleration within the soft bodied plankters ability to survive, so I've chosen motors that only turn at 105 rpm. The typical powerhead or pump turns at 1720 rpm.

 

 

Although the prop blades only turn at 105 rpm, their 8" size moves a tremendous volume of water at slower speeds. I think the same 60 watt motor in a powerhead or low rpm motor will move the same volume of water, but the slow motor has perhaps one thousandth the G force of a powerhead.

 

This method may not end up working for you, but before dismiss it, consider this: The Aquarium of the Pacific, in LA, uses a plunger system similar to what I linked to that is ~3 feet in diameter to move water in their 142,000 gallon kelp system. I would bet that one that moves ~5 gallons of water in a 3000 gallon system would create a 2-3" standing wave once adjusted correctly. The key is to adjust the plunger frequency to the natural frequency of your tank. Think about playing in the bath tub as a kid and moving back and forth a little bit, but getting all of water in the tub to oscillate doesnt take that much energy to maintain once established. Oscillations at natural frequency are amplified by the system.

 

IMO, the only reason that this is not a more popular means to move water in our tanks is because it requires pretty invasive modification (plumbing), and some good DIY skills to make happen.

[Chad]

Jon and others, please give me your opinion. Is it more important to have a surge device or in-tank water flow? While the ideal answer would be "both", with a tank this large I have to be mindful of my utility bill.

 

Lifting water requires more energy than simply circulating it. Let's suppose that filling a 50 gallon Carlson device at 2' of head in one minute requires 200 watts of pump power. That same 200 watts might drive a propeller at zero head to move 8,000 gph in the tank. I would like to do both, but I think the priority is to get 20x tank turnover on the fewest watts possible. I think using an air device to lift water into the surge device is a great idea, but I haven't figured out the mechanics. I'm not the best mechanical mind around.

 

Do people agree? Is it likely that the gravity of the water weight falling from the surge device will pull a lot of tank water along with it, and the 200 watts of surge power may circulate the same volume as a 200 watt powerhead. If so, count me in.

 

IMO, random flow is more important than either. And it can be achieved with either method. You are probably correct about lifting the water, but the effect is dramatic because all of the energy used to lift the water is released very rapidly during discharge. Additionally, you could lift the water by unconventional (although probably less efficient overall) means such as air lifts. I would think that effective use of propellor driven devices would work for what you need it to.

[dave w]

This method may not end up working for you, but before dismiss it, consider this: The Aquarium of the Pacific, in LA, uses a plunger system similar to what I linked to that is ~3 feet in diameter to move water in their 142,000 gallon kelp system. I would bet that one that moves ~5 gallons of water in a 3000 gallon system would create a 2-3" standing wave once adjusted correctly. The key is to adjust the plunger frequency to the natural frequency of your tank. Think about playing in the bath tub as a kid and moving back and forth a little bit, but getting all of water in the tub to oscillate doesnt take that much energy to maintain once established. Oscillations at natural frequency are amplified by the system.

 

IMO, the only reason that this is not a more popular means to move water in our tanks is because it requires pretty invasive modification (plumbing), and some good DIY skills to make happen.

 

 

Then I will look into this type of system. I am a little fearful of an acrylic cylinder moving inside an acrylic pipe, it seems to me that grains of sand will soon scar it up. But there are many ways to modify the plunger. My first impression is that it looks expensive, but I may be wrong. I tried looking into diaphragm pumps but was turned off by the cost of industrial sizes.

[dave w]

IMO, random flow is more important than either. And it can be achieved with either method. You are probably correct about lifting the water, but the effect is dramatic because all of the energy used to lift the water is released very rapidly during discharge. Additionally, you could lift the water by unconventional (although probably less efficient overall) means such as air lifts. I would think that effective use of propellor driven devices would work for what you need it to.

 

You're probably right about random flow, I will work on this once I can effect high tank turnover with slow moving equipment. There are a lot of problems that can be handled with high rpm pumps, but they don't support "plankton soup".

 

My attempts to use slow turning propellers probably begs the question "why is a plankton system important?", and I think I owe an explanation. I'm trying to use plankton and high plant biomass for high water quality because I think the many millions of plankton are our largest water purifier. At 25 plankton per drop and 90,000 drops per gallon, even a 55 gallon tank has 5 million plankters, making them the largest biomass of our tanks, just like the reef.

 

I'm doing a plankton system because I will be basing my tank on more than corals -- the sponges, shellfish and other filter feeders of the reef which do best when consuming lots of plankton while producing millions of their own plankton babies. For example, 200 oysters from the Chesapeake at maturity will not only clean 10,000 gallons of water a day, they spawn up to a million larvae 3 or 4 times a year. That's an average of 2 million plankters a day in the 30 to 40 micron range that pygmy angelfish larvae like. Sponges shed lots of cilia into the water column which are an important coral food. Refugiums produce millions of copepods (even benthic copepods and other organisms produce planktonic larvae). So if most of our tank produce free floating larvae, and I move water at speed that don't harm them, the tank may teem with clouds of animals. Add in a constant drip of phytoplankton, and I hope to mimic the reef in a way that I haven't seen in other systems yet.

 

I hope this is a wrinkle that will make me a better reefer. It is challenging because it means unplugging high flow water pumps and protein skimmers, both of which remove plankton as fast as our tanks produce them and both are extremely useful tools for water quality. It may not work.

[Coral Hind]

My thinking is that a 200w zero head, constant flow doesn't seem as dramatic when compared to a 200w flow being stored in a container and then dumped all at once. That 200w flow becomes stored energy and is like a wave of 1000w flow. To me that would keep detritus in suspension and move corals better. Just my thoughts on it.

 

I think the constant plankton idea is interesting and I will be watching this build thread closely. If you need help with the build the post it up, I'm sure people will be willing to help out.

 

 

[dave w]

You could use a high torque servo for r/c airplanes to move a fin back and forth in the upper water column. If you were to put it in the center of the "U", between the 2 scrubbers, it could be used to generate surge and more effectively circulate the water without shredding plankton. Maybe you wouldn't even need the big bladed pumps and just use the geyser pumps.

 

Rob, sorry to be late answering this post. This sounds like a fascinating idea, but it is just a little over my head. Can you either explain it in terms my simple mind can grasp or show it in a diagram?

 

Only Rob has seen my sketchup design so far and others may not understand this explanation, but the 20' long leg of the tank has two refugiums just a few inches above the water line, fed by geyser pumps. If I use the geyser pump to lift water a little higher, the fuges could empty into a surge device which then dumps into the tank all at once. I think this is very workable because geyser pumps can lift water quite a distance. I'll post the sketchup of the tank when I can clean it up a little, its just that I'm a little embarrased at my crudeness.

[dave w]

Rob, sorry to be late answering this post. This sounds like a fascinating idea, but it is just a little over my head. Can you either explain it in terms my simple mind can grasp or show it in a diagram?

 

Only Rob has seen my sketchup design so far and others may not understand this explanation, but the 20' long leg of the tank has two refugiums just a few inches above the water line, fed by geyser pumps. If I use the geyser pump to lift water a little higher, the fuges could empty into a surge device which then dumps into the tank all at once. I think this is very workable because geyser pumps can lift water quite a distance. I'll post the sketchup of the tank when I can clean it up a little, its just that I'm a little embarrased at my crudeness.

 

 

Here is a picture of some of the block in place and some new footers which will support buttresses. The butresses will effectively break the sump into seven areas of about 300 gallons each. I am still learning how to post photos, sorry if this pic is a little small. And I know, one of the new footers is crooked, that will be OK.

[Coral Hind]

What is the reasoning to split the sump into seven areas?

 

 

[Chad]

After doing some thinking on how I would accomplish the piston surge device, then looking for cost on parts and all that, I think it would cost in the order of $6-800 to build (not that expensive if it adds a huge amount of water movement to your tank). You would need a piece of ~24" diameter PVC (schedule 80 costs 121 a foot) that is around the height of your tank, a 6" piece of 20" diameter PVC, a couple of 1" pieces of plastic discs ~21.5" in diameter for the piston (20" dia. 85 a foot and you could probably get 1" acrylic from a large tank builder scrap for almost nothing, then cut it yourself), a stout DC motor, some gears/pulleys, and some odds and ends to make it all work.

 

I think you are right that the clear acrylic tube and piston looks expensive (I have looked into acrylic tubing in large diameters before... wow it is costly). I was thinking a better way to do the piston would be to have a smaller diameter tube capped on both ends with a piece of 1" (or so) plastic.

[zygote2k]

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.

[dave w]

What is the reasoning to split the sump into seven areas?

 

I didn't want to split the sump into 7 seven areas, but my brother reminds me that the exterior block wall has 6' of ground pressure against it and needs support. Usually a block wall has the weight of a house to hold that pressure, but this one doesn't. So I'll use plenty of steel and the buttresses. I can join the seven sumps together if there is a compelling reason, what do you think?

[dave w]

After doing some thinking on how I would accomplish the piston surge device, then looking for cost on parts and all that, I think it would cost in the order of $6-800 to build (not that expensive if it adds a huge amount of water movement to your tank). You would need a piece of ~24" diameter PVC (schedule 80 costs 121 a foot) that is around the height of your tank, a 6" piece of 20" diameter PVC, a couple of 1" pieces of plastic discs ~21.5" in diameter for the piston (20" dia. 85 a foot and you could probably get 1" acrylic from a large tank builder scrap for almost nothing, then cut it yourself), a stout DC motor, some gears/pulleys, and some odds and ends to make it all work.

 

I think you are right that the clear acrylic tube and piston looks expensive (I have looked into acrylic tubing in large diameters before... wow it is costly). I was thinking a better way to do the piston would be to have a smaller diameter tube capped on both ends with a piece of 1" (or so) plastic.

 

Truthfully, it seems a little daunting to me, but I'm willing to explore it. I'm looking at how to turn over 3,000 gallons up to 20x per hour with the least amount of energy. If a piston accomplishes this, I will go with it. Intuition tells me that air lifts and propellers are efficient, but maybe that is just my traditional mind talking that is a little afraid of unknown new ideas.

[Integral9]

Humidity will be a large problem, especially in winter. At Justin Capps recommendation I will keep polycarbonate covers on the tank in winter to reduce humidity and slow heat loss. I will install an air-to-air heat exchanger to flush out humidity and recapture as much of the heat as possible.

 

I was originally going to put this tank in my basement office, and my wife was constantly worried about humidity and leaks. I can't describe the look of relief on her face when I told her I would build the sunroom addition for the tank.

 

I will circulate with low rpm pumps and geyser pumps to keep plankton alive, so the excellent Hayward pool pumps will not work here, although I'm pretty sure you were joking. I don't know what the Swimjet is.

 

 

I'll have to look up those air-to-air heat exchangers. I'm not familiar with them, but sounds interesting.

 

Yeah, i suppose pool pumps aren't designed for salt water environments. I'm not that familiar with planktonic setups and wasn't aware of the low rpm need either. Makes sense though. As for the swimjet, the low rpm need is also going to be a problem there. But they are basically pumps installed at one of a swim-spa or pool. When someone turns them on, they create a jet of water strong enough to swim against, like a treadmill.

 

I was thinking you might with an auto-cover setup on a timer to open and close. outdoors this would not be reliable as sticks a leaves will jam up the tracks, but indoors I think it could work. also, when it's open it's not going to do anything to hold the heat in.

[Integral9]

you might want to explore the agricultural methods for lifting water and scale them down. Here is a link to the UN's html version of the "Water Lifting Devices for Irrigation". i think you might be able to use one these devices to fill a volume for a surge. There are some interesting options in there that I hadn't thought of.

 

http://www.fao.org/docrep/010/ah810e/ah810e00.htm

[dave w]

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.

 

Quite complex for someone like me who prefers simplicity. But I'm willing to do anything that works.

[dave w]

I'll have to look up those air-to-air heat exchangers. I'm not familiar with them, but sounds interesting.

 

Yeah, i suppose pool pumps aren't designed for salt water environments. I'm not that familiar with planktonic setups and wasn't aware of the low rpm need either. Makes sense though. As for the swimjet, the low rpm need is also going to be a problem there. But they are basically pumps installed at one of a swim-spa or pool. When someone turns them on, they create a jet of water strong enough to swim against, like a treadmill.

 

I was thinking you might with an auto-cover setup on a timer to open and close. outdoors this would not be reliable as sticks a leaves will jam up the tracks, but indoors I think it could work. also, when it's open it's not going to do anything to hold the heat in.

 

Actually if swimming pool pumps can handle the chlorine in a pool they could probably handle salt water. But I need low speed. The auto cover sounds like a great idea. It would be easiest in a rectangular application, turning it around a U-shaped horseshoe tank sounds like a challenge.

[dave w]

you might want to explore the agricultural methods for lifting water and scale them down. Here is a link to the UN's html version of the "Water Lifting Devices for Irrigation". i think you might be able to use one these devices to fill a volume for a surge. There are some interesting options in there that I hadn't thought of.

 

http://www.fao.org/d...0e/ah810e00.htm

 

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