Designing and executing an aquarium project for a 2.800 liter Malawi community tank - Part 1
(Notes on the design. construction, set up, aquascaping as well as the composition of the livestock).
By Andreas I. Iliopoulos
At the end of April I received an e-mail message of my good friend and devoted hobbyist Takis Tsamis. It was, in fact, an e-mail he forwarded to me as he had received it himself from the representative of Atlantica Hotels, who was responsible for the interior design of the hotel and she was thinking of installing an aquarium system in the reception. The reception was located in the lobby of a new hotel that the “company” Atlantica Hotels Inc is building in the island of Rhodes.
I immediately contacted Mrs. Esperantza Michaelidou in Cyprus for more details. To make a long story short, I’ll say that we managed to fix an appointment in which the engineers who were in charge as well as the technicians and I would meet to discuss this project. This meeting finally tool place in the place where the aquarium was to be constructed. me in situ, meaning at the building site itself.
I had the opportunity to meet with two very nice men (Vasilis Pavlou and Dimitris Kavadias), discuss with them about the details of the project, inspect the place where the aquarium would be installed and try to find out the best approach to finish the project. We reached a deal fairly quickly and then I lost my sleep thinking of the many details that had to be taken care of.
The final plans were for a tank with the following measures: two meters and eight centimeters by one meter by one meter (280 cm x 100 cm x 100 cm – Length x Width x Height) with a face of two point eight square meters (2,8 m2). The total volume of this tank climbs at the two thousands eight hundred liters (2.800 l).
The kind of the system? What else? Malawi community tank!
It took four specialized craftsmen working for four days to construct the glass container. The thick and heavy glass plates came by ship from Piraeus to Rhodes. We had to use a derrick to disburden the wooden box, where the glass pieces were packed safely, due to the weight of the load. About nine hundred kilos (900 kg) of glass!!! But the package was unloaded at the entrance of the facility, as the arm of the derrick was not long enough to bring the package exactly where the tank was to be built. Now what?
Men power, of course. Twenty four workers (!!!) gathered around the heavy and barely manageable wooden package, they lifted it by hands and they took it to a place near the construction site, about twenty meters away. The package was placed in a vertical position, because I didn’t the glass panels to bend as this might lead to an unsafe construction. The expert craftsmen would work with it after 48 hours so the long and heavy glass panels would bend if left without any special care.
The construction of this tank proved to be more difficult than I anticipated. On one hand were the extremely heavy glasses and on the other hand it was the place itself. You see the tank would decorate the lobby of the hotel. It was going to be installed on the wall already built behind the reception. So we had to order a worker to dig out a rectangular hole to take the tank in. Second, we should install the aquarium on a heavy-duty stand, “tied” on the wall itself. The carpenter of the company dug gutters on the lower part of the “window” which we opened. These gutters were placed twenty two centimeters from each other. In these gutters horizontal wooden beams were placed, which would be part of the stand. These beams measured twelve centimeters by eight centimeters (12 cm x 8 cm) in cross-section. The rest of the stand was constructed by the same kind of beams. The height of this stand is one meter and twenty centimeters (120 cm). I suppose, you can imagine the difficulties now.
When the stand was secured in place using cement, I used five centimeters (5 cm) thick natural cork plates as the surface on which the bottom glass would be placed. It was time now to start the construction of the tank. Another difficulty was that we should place the front side of the tank five and a half centimeters (5,5 cm) out of this wall as after we finished with the tank, the reception wall decoration would be added on the wall. This would consist of sandblasted glass surfaces on the wall of the reception and around the tank. So the tank's front panel would finally be at the same level with these decorative plates.
We used special suckers to handle the glass panels, which were cleaned thoroughly from dust, oil (from the cuts) and human fats (from handling them), with plenty of water first and lot of pure alcohol as the last step. It took four days to be finished, as we had to wait for the silicone to dry completely before proceeding to the next step.
We used the same method that I have already described and I use for the construction of tanks. Along with the five glass plates that the tank is mainly consisted of (bottom glass, front glass, back glass and the two side glasses) there were glass beams running horizontally on every of the four sides of the upper and the lower side of the construction. Finally the tank was there standing, waiting for the rest of the work to be done. When the silicon dried I filled the tank with water to check its water tightness and to rinse the inside as well. We then removed the water and I left it for two more days to dry before proceeding.
To start with, the dimensions of the tank called for a glass thickness of nineteen millimeters (19 mm). The rest of the material that were used and the details of the construction will follow. I had to think about the filter system too and then about the most difficult part, which is the livestock. The livestock should be taken into account both for the estimated maximum bioload as well as the compatibility of the various species that would have to live together in this system.
Since the volume and the of the tank was known, I already knew that I should go for something big. So, after doing some research I finally I made up my mind and ordered the following:
My rule of thumb has nothing to do with the ones normally applied in these cases. Statements like: “three times the total water volume, four liters per centimeter of body length” and the alike leave me totally indifferent.
My rule of thumb is: “the MORE, the BETTER, although I shall never achieve the best”, meaning a naturally balanced system.
So I set the limit of the water turnover to sixteen thousands five hundred liters per hour (16.500 l/h), which means that the whole water volume will pass through the filters and their media more than six times per hour. I calculate it this way, as the decoration items (substratum, stones and big rocks) will consume a lot of the initial volume. I also said that I set my limits; and that is the truth as one of the standard subjects of such a project is low cost as well. And cost is not calculated as just spending for buying equipment (which is money only spent once), but include daily power consumption and maintenance in general.
So I ordered for the water circulation three (3) water pumps:
One (1), with a turn over of three thousands five hundred liters per hour (3.500 l/h); and a max head of three meters and thirty centimeters (3,3 m), from AquaMedic. The model is OR3500 of the Ocean Runner series.
Two (2) more water pumps ordered from AquaMedic as well. Those have a turn over of six thousands five hundred liters per hour (6.500 l/h), each; and a max head of three meters and eighty centimeters (3,8 m). The model is OR6500 of the Ocean Runner series, too. The three pumps will circulate and drive water through filters’ media.
OR3500 consumes sixty-five Watts (65 W) and the OR6500 one hundred fifteen Watts (115 W). Following Robert (Bob) Fenner, I can calculate now the daily cost as far as electrical power is concerned. So I have a sum of one hundred and eighty Watts (65 + 230 = 295) for twenty-four hours a day. This makes us four point thirty-two Kilowatts (7,08 kWh), which multiplied by the electrical rate gives the final cost (if we calculate with a relevant cost of €1,071 that our Local Electrical Company charges per kWh we have just €7,58 daily).
The rule of thumb: “The function of filtration MUST have three (3) stages: Mechanical filtration, Chemical filtration and – last but not least at all – Biological filtration” covers my desires, completely. I only modify this rule according to the specific project, so it suits in a particular system. So I ordered one modular filtering unit, made by LIFEGARD. The unit consists from six (6) heavy-duty PVC tubes.
LIFEGARD’s hexad of modules, with already unscrewed top cups
The upper side of the unit
1. Mechanical part
Two out of the six tubes will serve as the mechanical part, as they shall be filled with the mechanical cartridges which come along with this particular system. These cartridges are able to hold particles of even five (5) microns.
The mechanical cartridges before their installation within the pipes of the unit.
As mechanical media can be clogged and therefore some kind of maintenance will be needed, LIFEGARD managed to install on this filter unit a manometer. The reason for that is that media are not visible (these modules are not transparent), so the user should know when the mechanical media need to be cleaned. As long as the pressure in the unit does not exceed nineteen (19) bars, the system works fine, but larger pressure dictates for maintenance. The unit comes with six (6) mechanical cartridges; and as long as I am using only two (2) tubes I am left with four (4) other clean spare cartridges. So when one must clean the ones installed, he replaces them with two from the stored and clean ones and so on.
The manometer on the right will detect the time for servicing the mechanical parts of the filter.
2. Chemical part: Three (3) more cartridges of the same unit will be host the chemical medium (super activated carbon).
Two (2) of the mechanical cartridges and Bio-Chem stars have already placed in the unit.
3. Biological part: One (1) of the rest tubes will be loaded with Bio-Chem stars, as well, to have a small biological cultivation within this very unit. But biological filtration would not be completed by this.
I had a lot of thinking to do about this issue. On the one hand I wanted to care about the capability of the system, while on the other I had to pay attention at the available space for installing the system as only the front glass window will be obvious for the clients and the visitors of the facility, while the whole thing will be at a room, behind the reception; and in the same room employees will work on their desks. Another issue was cost as well.
So I chose a unit of a trickle filter made by AquaMedic. The unit has a height of one hundred and seventy centimeters (1,70 m) and a diameter of twenty five centimeters (25 cm). On the top of it and on the place where water from the system enters the unit there are two (2) artificial sponges for aquatic use, so some particles that weren’t removed from the main mechanical filtration system will be held here.
I placed this tall unit on the tank, feeding it with one of the two OR6500 water pumps.
The water inlets on the upper part of the trickle filter.
The two (2) outlets – in the lower side of the unit – return water back into the tank.
The water outlets of the unit. The thin chain which secures it to the wall is visible..
The tall Plexiglas column, filled with two hundred liters (200 l) of Aquamedic bactoballs, was secured by a thin chain on the sidewall.
The two OR6500 water pumps feed both filters while the third (OR3500) is used just to keep a constant movement on the water surface. The two OR6500 are feeding the filters through two overflows, I have ordered to be drilled on the backside glass plate. This utility will be useful if someone wants to change the set up from a Malawi community tank to a marine system, to feed a sump through these overflows.
Lighting, as we all know, is an essential topic. Since I am not planning to set up a heavily planted or even an average planted system; and because the plants I’ll use (if any) will be easy going and hardy ones, I haven’t exaggerate. For the depth of one meter (1 m) and for the volume of the two thousands eight hundred liters (2.800 l), a total of seven hundred and twenty Watts (720 W) of lighting power is more than enough. The proportion climbs up to point twenty-five Watts per liter (0,25 W/l), which means plenty of algal growth for m’buna, while not much light to grow pest algae in the system. The equipment I have chosen for this purpose consists of two industrial hoods each carrying a combination of two Metal Halide with an output of one hundred and fifty Watts each and two blue actinic fluorescent tubes with an output of thirty Watts each. The MH lamps produce a color temperature of fourteen thousand degrees of Kelvin scale (14.000° K) and they are meant for marine use. The blue actinic ones range in a spectrum between the four hundred and four hundred eighty nanometers (400 nm – 480 nm). These pendants are made by ARCADIA. The items are manufactured from marine water corrosion resistant materials and they do have two separate timers installed on each. They are both Slimline ‘3’ series’ models and they have a length of one hundred and ten centimeters by a width of thirty-eight centimeters (110 cm x 38 cm) each.
As I have already decided about the “character” of this particular system – that it will be set up as a Malawi community – the items for creating the artificial micro-environment are limited to sand as a substratum, while big rocks and stones will serve as material for building rock piles on the back and in the center of the tank’s space.
The last, were found in nearby coasts, while four hundred liters (400 l) of especially made “Hydrocarbonate” sand were ordered from AquaMedic.
My idea was to create a coastal reef-like heavy system, along with a mid-water one connected together by a low arcade. This complex will be utilized by the m’buna species I want to house in there. The rest of the space will be left as an open sandy area, for the rest of the animals, which will be species of Malawi haps. I also want to paint the back of the tank (the outside) with an acrylic, non-toxic dark colored paint to simulate the deep-water effect. Ideas about using live Vallisneria sp. Plants, are also examined, since they will make a path with live seaweed-like plants when they grow (and send out runners).
With the valuable help of Giorgos Pastrikos, a hobbyist from Rhodes island, thus a knowledgeable person, as far as the sites I could find adequate amount and kind of natural materials (stones, rocks and very large rocks) was concerned we finally ended up to Gadouras river bank. He knew a place where a lot of rocks are gathered and he took me there. We collected about six hundred kilos (600 kg) of stones, rocks, large rocks and very large rocks.
To start with, I used a twenty millimeters (20 mm) thick styrofoam plate to cover the glass bottom, glued with silicon on the plate. With this material I was able to place the heavy aquascaping material inside the tank.
Detail of the styrofoam plate under the aquascaping material, before adding the “hydrocarbonate” substratum.
So, I had to find the material, to carry it about twenty kilometers (20 km) to the hotel, to wash it thoroughly and to carry it again inside the facility. Then I should start “building” the rock piles
Starting aquascaping …
I used a ladder to enter and exit the tank and George (thank god), one of the employees, to help me with the heavy stuff. I had all the rocks and stones on the floor and as I was making the piles I was choosing the next rock or stone. Well George was very helpful to give me the particular piece without having to exit the tank to pick it up myself. In several cases, other persons helped me to lift a rather heavy rock on the top of the ladder and place it in its place. The problem was that several times we had to remove one or more of these stones or rocks and replace them with others which seemed to fit better. Step by step the aquascaping was constructed.
Continued in next page