dave w

By overhead tanks do you mean the refugia? The depth is still open to discussion and I'd like people to chime in. Generally I want the refugia to be in full sunlight, high water flow, large surface area for dissolved oxygen, shallow sand bed and removable algae screens to feed the fish. This is a tall order but I think it can be done. I'd think anything from 3" to 8" depth would be appropriate. What do you think? Up to now I've sketched four overhead refugia with as much as 15 square feet of surface area each. I've sketched them around 18" wide and 10' long. I can't guess how many gpm's each will handle, but I like the idea of also using them to power a surge system. I'm open to suggestion.

Rob, this is a very generous offer. When the sunroom is dried in, we will finalize dimensions on the cylinders. Thank you.

The weekend was too busy with kids, but I'll get in a few hours this morning. It is my intention to power the connecting pipes (which turn the horseshoe into a doughnut) by geyser pumps because it appears geysers move the most water with the least energy. I believe in the old saying "it's cheaper to put air in water than water in the air". I'd prefer to power everything by air if it significantly cuts the power bill. If I lift the refugia from a few inches above water level to 18", I could drain the refugia into a surge device and do much of the 20x hourly turnover. I need to experiment with geyser pumps to see how much water flow they create at this head with a 2,000 cubic inch per minute air pump. If the geyser lifts water easily, I am thinking of raising and enlarging the refugia. But there are other issues. Large air volume from a geyser pump shooting water into the refugia may be noisy, and I may need to build a box to dampen this noise. I could even use the escaping air flow to power something. If the box has the water outlet below the water line it may also handle any bubble popping/salt creep issues. When I have time I'll sketch up my idea for discussion. Many things to work on.

Here is a pic of the east half of the tank. Not as exciting as the progress of the west half.

Thanks for donating your time, Chad. At this point I'm thinking of 6" pvc pipe as the first choice for the cylinder and Acrylic for the pistons. I have some 1" acrylic left over from the 600 gallon tank I took apart. I'm thinking an acrylic circle cut by a 6" hole saw might be just the thing. If I cannot find a 6" hole saw then I lean toward 4" dimensions. The inside diameter of the pipe and the outside diameter of the acrylic circle should match. If not, it would be easy to sand a light layer off the acrylic circle, but probably hard to add material if needed to make them fit.

I know you're joking, but it's hard to get a pic of the tank without a wide angle lens, so I have to keep taking two pics to cover it.

Thanks for the encouragement Dave. I am excited about the pistons and matching the wavelengths on the three legs, although I don't know how to keep both pistons in time. My immediate goals are finishing the block, framing and roof, then welding the stainless steel angle frame. Even after the tank is glassed and filled, there will be months to install and fine tune the systems. Curing the live rockwork will be a month or two all by itself. That will probably be when I have time to build the pistons. Right now I want to get "dried in" so the cold weather can't keep slowing me down.

This seems like a great idea if I could get the formula right. I know Aquatic Ecosystems used to sell a solution of other salts that just needed NaCl added. When I looked at it 20 years ago it appeared just as expensive to buy my chemicals at retail as to buy a pre-mix. What do you think?

Welcome to the thread mogurnda. Activity had died down a little and I worried that I was coming across as preachy. Somebody please kick me, or at least put me back on the path if they start to see that happening. I have been thinking of this tank for a while, but had settled on a 1,000 gallon tank in my basement office with 8 solartubes for lighting. Then Rob mentioned to put it in the sunroom and my wife enthusiastically supported getting it out of the main house. So here I am. In order to triple the size I have to finish the kid's basement at the same speed so my wife stays happy.

I will check out monsterfishkeepers.com tonight. It's true that I will have 24" or so water pressure on the blocks, but even an occaisonal dry sump could do me in of the pressure of the earth is to high. So I have to design for a worst case scenario. I probably don't need every device used here: partitions as buttresses, the horizontal steel and filling every block core with concrete and steel. But it only takes a few hundred more in materials to give me peace of mind. If this tank broke, I couldn't transfer the items into a few 55's until I fixed it. And because my labor is free, I think i will be less than $5k on the whole thing. So a few hundred in extra material isn't going to be on the top of a bunch of other cost overruns. And my back hurts literally as much as yours does figuratively. I hadn't laid 10" block before and boy are those suckers heavy.

I got a day off work and put in some block. Here is a pic of the west half of the tank. The bottom courses of block are 10", and they come up about 30" until the 8" blocks begin. This leaves a 2" ledge to sit the back of the tank on. The inside of the tank are the slimmer 4" blocks, because they have very little weight and no shear pressure. Typically a house uses 8" blocks, but it also has the weight of the house and roof to hold back the ground pressure. Because there is no such weight here, I will put a #4 (1/2") rebar in every block hole and fill the hole up solid with concrete when the wall is full height. If you look closely you will also see two #4 rebars laid horizontall in between each course of block. This is to resist the shear pressure of the ground. Finally, I increased the number of sump dividers (buttresses) which are 30" high. These butresses give perpendicular support to the wall, so effectively instead of having 6' of ground pressure, there is only 3.5' of ground pressure on unsupported block. If you have trouble sleeping, just read this post three times in row. I will post anothe pic of the east half of the tank later today.

A couple more points about feeding. Without a doubt, high quality food makes fat broodstock produce high quality eggs with better larval survival. But as the infamous Joseph Stalin once said "quantity has a quality all of its own." A dozen pygmy angel harems will be 35 females, each capable of releasing 300 or so eggs a night. That's 10,000 potential eggs per night tmes 50 days until metamorphasis is half a million eggs. Even if I only get 5 percent of this amount, that's a lot of caviar. I may only attempt to raise a thousand eggs over this 50 day time period because 2,000 gallons of copepods and a few hundred gallons of phytoplankton may only support one batch of larvae. Egg quality is critical to professionals economizing their larval efforts, but I may rely on the Joseph Stalin approach. It also appeals to me to mix eggs of a dozen species in the same batch to see who responds better to the feeding protocol. Even after saying all this, I only give a 5% chance of success. I will breed 50 angels purely for fun because there no profit in fish breeding. But I can still dream of producing a batch of lemonpeel x eibli's, can't I? Also, it is not hard to selectively feed. Say I got lucky enough to get a pair of golden angels(!) I could put them in one of the sponge refugiums by themselves and feed them blackworms until they burst. Even in a community tank I have selectively feed with a turkey baster. And with a large fish population, it is economical to use a blender to make a batch of high quality food and freeze it into thin sheets in plastic bags. The part of this blend made from fresh, high vitamin fresh seaweed can be pulled from the refugium. Finally, I don't want to make the wrong impression. I'm not recycling the refugium to save on food costs, I'm doing it to reduce food input and resulting water quality problems.

Your experience trumps my theory, although there is room for both. Eliminating an $18,000 light bill covers a lot of other expenses. Breeding fish do need a high fat diet, but raising one batch of centropyge larvae at a time isn't as daunting as fattening a broodstock of 50 angels. But it sure will be fun to watch a dozen harems courting and spawning in the evenings. I haven't communicated clearly that I see the refugium/fish food/water quality as a single issue. Algal metabolites start to leak when pods graze down new filamentous algae growth in the fuge after 14 days. Daily recycling one fourteenth of the fuge algae back to the angels as fish food means (theoretically) that I never have to add food to the tank. This reduces the problems of water quality/filtration/water changes as well as their expense. Fuge recycling closes the feeding loop and maintains water quality by removing my need to feed my fish. I am the most dangerous threat to my tank. Using the large algal biomass as food especially fits my desire to keep and breed lots of pygmy angels because filamentous algae is their favorite food. So I'm trying for a balanced equilibrium between fish, plants and plankton. I don't know how well it will work. Theory is easy, reality is hard. In spite of my points here there are no absolutes, I will still add food, drip microalgae, have water quality problems and use various filtration methods. In a year you may even find me building a giant skimmer.

That's a good point, and a good reason for water exchange. Generally, most phyto and zooplankton have different parameters where they do best. For example, I may grow some types of freshwater or eurohaline organisms and algae, then get double use of that water by using it to make up evaporation losses while also feeding the tank. 2,000 gallons of sump may be enough room for freshwater food. I don't know because all my work has been on saltwater environments.

I can even take my waste salt water, treat it with chlorine/sodium thiosulfate, then recycle it through the phytoplankton vessels. With the vitamins added in this process anything lacking from the original water may not affect the algae. For a while, the changed water can be used to fill the sumps, artemia in particular can live through just about every harsh environment known. They are just amazing creatures. For example, they still keep 9ppm salt level in their blood when surrounding waters are as high as 300ppm, an incredible osmoregulatory feat. Their ability to live in levels of all kinds of toxic ions almost classifies them as extremophiles.

I won't be doing it much. One reason I went with a large tank is because I opt for a higher initial cost but low maintenance cost. For example, 7 watts per gallon would be 21 kilowatts per hour at 15 to 20 cents would be about $40 a day at 12 hr illumination. That's $12,000 a year, at least double the cost of my entire sunroom, whereas full sunlight is free. The same for sump pumping and skimming (water changing). Three thousand gallons of water weigh twelve tons, the electricity to lift that 4 to 5 feet several times per hour would be costly and kill plankton, so I opt for cheaper in-tank circulation only. If I need to exchange tank water with sump water in mid summer or mid winter for temperature moderation, I will probably use a traditional water pump. If I use the sumps for feed animals, I will use trap them by appropriate sized screens, then lift up the gallon of culture water with the food. For example, if I want to harvest copepod nauplii but keep the adults in the sump chamber to make more babies, slow water flow would pull nauplii through a 53 micron screen which excludes adults. Inside the 53 micron screen is a smaller screen hooked to a pump to remove water from the trap and keep a positive flow, but keeps the pod nauplii suspended in the trap for harvest. I will unplug the skimmer because it is a plankton trap and because the trace elements removed require water changes. A twenty percent monthly water change would be 600 gallons at 25 cents a gallon would $1,800 per year. To a large extent I hope this can be avoided. Please keep in mind that I am not a purist. I will supplement trace minerals and everything else necessary for a healthy system. If necessary I will do water changes, flow through the sump carbon filtration and protein skimming. I think a plankton system is a wrinkle that will solve some problems but also create new ones, and I have yet to learn what the new problems will be. I am open to whatever makes a healthy system more closely mimic the reef. Higher plant biomass, lower bacterial biomass, high plankton, continual feed of live phytoplankton, harvest of filamentous algae from the refugium to feed herbivorous fishes and thus eliminate (mostly) the fish feeding that raises nutrient levels, heavy natural filtration through sponges, oysters/shellfish, heavy reliance on filter feeders, and more algae. Hope I don't come across as preachy. If so I apologize, that is not who I am. This will be a fun adventure for me and may give something back to the hobby.

Good point on the treated lumber, which I will now avoid. I will either fiberglass wrap regular lumber or treat it with Sweetwater two part epoxy paint. I have to do this to the bottom of the plywood tank anyway. I agree that the back corners of the sump will be almost impossible to reach and that the sump will have little, if any exchange with the main tank. I've never counted the sump as very important in this type of setup unless it helps with temperature moderation. It's just extra space for live foods or storage. Given the 5% chance of sucess with larval angelfish it could be used for growout, but odds are really slim at succeeding with these fish.

Good point. I was planning on using treated lumber with two coats of a high quality white latex primer. The composite lumber I'm familiar with are 5/4 by 6" used for decking, but I don't know of any two by fours made of this material. What would you recommend?

You're right. With 5,000 gallons the whole room will need ventilation, so I will buy a heat exchanger, which captures about 75% of the heat from inside air and uses that to warm up the outside replacement air, which is low humidity. I will use two by fours to span the 36" to 48" of the tank from front to back. I planned two by sixes but my dad, who has been a builder and architect for a long time pointed out that with a 3/4" plywood deck the beams are only carrying 8 pounds per square inch and two by fours will do. Every inch matters to get an accessible sump, have the largest viewing area possible, and still be able to reach across the top of the tank without standing on tiptoe.

Ha, ha, ha! Nobody's going to make me come to my senses. Of course the sketch shows part of one of the short legs of the tank, for those with more imagination than Rob. Before I started this thread, Rob was a great source of advice to me on natural systems, using a sponge refugium to replace skimmers, etc.

Ventilated? I didn't know the sump needed ventilation. Good thing you told me because I am doing the block today and must put in some kind of hole. What do you recommend?

OK, after some work, I have another sketch showing the glass sump doors and some of the proposed finish work. The 2 x 6's shown here will be replaced by 2x4's, so the red band of granite shown between the sump and the tank will be slimmer than the diagram. I will use the same color granite around the top coping. I have a granite saw and slabs to make these, but I may find that long thin strips of granite are fragile and I may need to use marble. Either way, I prefer the look of long pieces over tiles. A piece of steel angle holds up the stone. The grey floor shown here isn't very accurate, I will use a travertine marble which is more ivory colored. Another advantage to marble over granite is that marble can be drilled, making installation of the stainless steel hinges on the sump doors much easier. The six vertical stainless posts where the acrylic panels meet will probably also be covered with the same granite or marble. A final design criteria is that the height of the top must be less than my armpit height of 56 inches, so I don't have to stand on my toes to reach anything.

Although the sumps will be 24" under the floor, the top of them will be at floor level and I will have access through the 16" glass doors below the tank. With a nearly white floor and 400 feet of glazing overhead the glass sump doors may let a fair amount of sunlight in. The glass also permits use of a garden hose for cleanup. The floor will slope toward a drain under the sofa. But I will be at least on my knees, and perhaps on my stomach if I have to reach very far back into the sumps. The rock will be quite a challenge. I can't afford a zillion pounds of Florida or Fiji live rock . With my construction background I lean toward thin (1.5 inch) cast concrete skeletons with lots of styrofoam passage holes (called knockouts), then covered by a lot of oystershell/sand/cement mixed with salt pellets to make something with structural integrity, but very porous. I can cast rods and holes to interlock the panels, but a realistic finish will take lots of handwork. One reason I went with 48" of depth (front to back) was to turn the coral walls perpindicular to the viewer with open sand areas in between. I think sandy "rooms" with walls on three sides will keep fish from seeing much of each other and reduce aggression.

OK folks, I followed directions and loaded the water flow sketch with better resolution. The two round tubes shooting toward you will meet each other and turn the horseshoe tank into a circular one to facilitate water flow. The green trays are refugiums. The rectangular blocky horizontal things are meant to signify water flows. I have about 14' between the two side legs of the tank, enough to put several people on a sofa and be surrounded by tank.

In that case I can use 6" pvc pipe and get a 6" hole saw for plywood or sheet pvc pistons. I don't have a large body of water but the blockwork on the sumps will be done soon and I can drape them with pond liner or a roll of EPDM rubber I bought to waterproof the walls. Can anyone recommend a good motor? This will also be a good place to put a 2" or 3" pvc pipe through an upside down 2 gallon bucket and see if the DIY geyser pump works.