Dave W's 3000 gal plankton/reef tank

[Coral Hind]

This thing is going to be sweet. How will you access the sumps? Are you going to use natural rock or some fake fiberglass structure like larger aquariums use?

[dave w]

This thing is going to be sweet. How will you access the sumps? Are you going to use natural rock or some fake fiberglass structure like larger aquariums use?

 

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.

Edited November 9, 2010 by dave w

[dave w]

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.

Edited November 9, 2010 by dave w

[zygote2k]

 

 

 

I knew you'd come to your senses- the small tank size looks great!

[Coral Hind]

How will the sump be ventilated?

[dave w]

How will the sump be ventilated?

 

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?

[dave w]

I knew you'd come to your senses- the small tank size looks great!

 

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.

[Coral Hind]

I would think that if it isn't ventilated that water would condensate under the tank and on the glass panels you are installing for sump access. I'm not sure exactly how to vent it but I wanted to make sure you thought about that before you got to far along.

 

What supports will run across the top of the sump to form the bottom of the tank?

[dave w]

I would think that if it isn't ventilated that water would condensate under the tank and on the glass panels you are installing for sump access. I'm not sure exactly how to vent it but I wanted to make sure you thought about that before you got to far along.

 

What supports will run across the top of the sump to form the bottom of the tank?

 

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.

[Coral Hind]

I would use plastic or composite lumber so the moisture doesn't cause it to fall apart. If you look at the wood 2x4's at Roozens you will get an idea of what yours will look like in a few years.

[dave w]

I would use plastic or composite lumber so the moisture doesn't cause it to fall apart. If you look at the wood 2x4's at Roozens you will get an idea of what yours will look like in a few years.

 

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?

[ctenophore]

No way on treated lumber. condensation + drip into sump = death. I would fiberglass coat anything close to water. Why even have the sump area if it won't exchange with the main tank? It sounds like it will be extremely difficult to work in with that minimal clearance. Reaching the back bottom corners sounds impossible.

[dave w]

No way on treated lumber. condensation + drip into sump = death. I would fiberglass coat anything close to water. Why even have the sump area if it won't exchange with the main tank? It sounds like it will be extremely difficult to work in with that minimal clearance. Reaching the back bottom corners sounds impossible.

 

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.

[Coral Hind]

How will you be moving the water from the multi chambered sump to the tank?

[dave w]

How will you be moving the water from the multi chambered sump to the tank?

 

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.

[zygote2k]

I still think you'll need to do at least monthly water changes. If you could run your waste salt water back thru a r/o filter, maybe you could save some money there?

[Coral Hind]

I definately think this is going to be a fun adventure and learning experience. I would think there should be some minimal water moving between the tank and sump to keep the water parameters of the two areas consistent.

[Coral Hind]

I still think you'll need to do at least monthly water changes. If you could run your waste salt water back thru a r/o filter, maybe you could save some money there?

The waste saltwater would be hard on the R/O unit and clog the filters very fast. Because the saltwater is thicker and has a higher level of dissolved solids, the water pressure has to be over 400psi to push it through a membrane. This additional pressure requirement for saltwater means all components are thinker and pumps must be larger. I think the cost of a saltwater R/O system would not make it worth doing.

[dave w]

I still think you'll need to do at least monthly water changes. If you could run your waste salt water back thru a r/o filter, maybe you could save some money there?

 

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.

[dave w]

I definately think this is going to be a fun adventure and learning experience. I would think there should be some minimal water moving between the tank and sump to keep the water parameters of the two areas consistent.

 

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.

[ctenophore]

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.

Large systems cost proportionally more to maintain than small ones. Sure, you'll save money on lighting but you still have water movement devices, even if they are efficient you still need to move 60,000+ gph. Water changes will be necessary, going bigger does not reduce the need for them. You will need a lot of carbon to filter all the algal metabolites, prob. 5 gal bucket/month. Fish food is expensive if you have a lot of fish, at least if you use high quality fresh/frozen food. If you want your angels to spawn you can't feed them flakes. I wouldn't worry about expensive bottles of trace elements that you can't test for. You will need to do some ca/alk replenishment, probably by kalk to keep pH up, which is cheap. You'll evaporate 20-30 gal/day so a decently efficient RO filter to not raise the water bill too much. 2:1 waste:good means around 60-100gal/day of which 2/3 of that can feed your plants/garden. Plan on spending for a high quality cleaning magnet as you will have a lot of view area to clean very regularly (every other day in sunlight), this means maintenance time.

 

Then comes the biggest expense of them all, temperature control. No matter how well insulated the building is (greenhouses are poorly insulated as a rule), you will need to heat it at night in the winter. Summer cooling may not be as much an issue, but if you want to try to raise fry then it may need to be tighter than what a normal softy reef could get away with.

 

A friend of mine that had a 1000g tank from 04-08 likened a large tank to a freight train. Once you get it rolling in the right direction, it has a lot of inertia and will keep going. But changing its course requires a lot of effort (and money). I'm just trying to give you a realistic approximation of costs as I've found them during my 5+ years of greenhouse reef adventures.

[dave w]

Large systems cost proportionally more to maintain than small ones. Sure, you'll save money on lighting but you still have water movement devices, even if they are efficient you still need to move 60,000+ gph. Water changes will be necessary, going bigger does not reduce the need for them. You will need a lot of carbon to filter all the algal metabolites, prob. 5 gal bucket/month. Fish food is expensive if you have a lot of fish, at least if you use high quality fresh/frozen food. If you want your angels to spawn you can't feed them flakes. I wouldn't worry about expensive bottles of trace elements that you can't test for. You will need to do some ca/alk replenishment, probably by kalk to keep pH up, which is cheap. You'll evaporate 20-30 gal/day so a decently efficient RO filter to not raise the water bill too much. 2:1 waste:good means around 60-100gal/day of which 2/3 of that can feed your plants/garden. Plan on spending for a high quality cleaning magnet as you will have a lot of view area to clean very regularly (every other day in sunlight), this means maintenance time.

 

Then comes the biggest expense of them all, temperature control. No matter how well insulated the building is (greenhouses are poorly insulated as a rule), you will need to heat it at night in the winter. Summer cooling may not be as much an issue, but if you want to try to raise fry then it may need to be tighter than what a normal softy reef could get away with.

 

A friend of mine that had a 1000g tank from 04-08 likened a large tank to a freight train. Once you get it rolling in the right direction, it has a lot of inertia and will keep going. But changing its course requires a lot of effort (and money). I'm just trying to give you a realistic approximation of costs as I've found them during my 5+ years of greenhouse reef adventures.

 

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.

[dave w]

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.

[dave w]

 

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.

[Coral Hind]

My back hurts just looking at all that block. I don't think you need the sump partitions as supports for the outside block wall. The walls are short in both length and height. Plus if you are filling the sumps with water you will have that water pressure on the blocks.

 

Have you checked out Monsterfishkeepers.com? There are a few large tank builds over there that you might be able to get some info from. Maybe learn from other people's mistakes.