Morten Nordby's (mortenN) Reef Aquarium

Introduction:

When I opened the email from Skipper I was confused. I looked at my calendar and no, it wasn't April 1st. Then I understood that he had found my tank and was asking me if he could use it as the Tank of the Month. I was very proud to be asked, since the tank was only 14 months old at the time. I never thought it was possible to build a system that would be considered Tank of the Month quality in so little time. I must give special credit to all the people on Reef Central who have responded to my questions the many times I needed help. I give a lot of credit to my wife, Elisabeth, who is also interested in saltwater aquariums and provides so much help to make this all possible.

I started my first saltwater tank in 1980. I have been in and out of the hobby a few times due to work-related issues, but my interest in marine aquariums has never waned. Today we are living in a different world with so many more technical enhancements, which is one of the things, along with 25 years of trying and testing, that made it possible in only 14 months to get onto Skipper's mailing list. Thanks again!

My philosophy for this tank was to create a small-polyped scleractinian dominated, bare-bottomed tank with a few special fish. In my 25 years of involvement in the hobby I have tried various fish-only tanks, fish with soft corals, fish with fleshy, large-polyped species, soft corals and small-polyped species at the same time. I have also been a keen do-it-yourselfer. In my early years of involvement in this hobby it was not possible to go to the local fish store with my credit card and buy what I needed, and I think this has given me a wider understanding of what it takes to make a saltwater aquarium succeed. In this 90-gallon tank I have tried to use all I have learned since starting in the hobby.

System Profile:

Main tank: 337 liters (90-gal.) - 75cm W x 60cm D x 75cm H, standard glass Sump: D.I.Y. 113.5 liters (30-gal.) Fragment tank: 113.5 liters (30-gal.) Return pump: Deltec 5250

Water Movement:

I use two Tunze 6100 Stream pumps in the main display tank. I run them at 100% - 30% in five-second intervals. I will say the Tunze Stream pumps were a tremendous technological advancement for devotees keeping small-polyped species. Although there is no good place in a 90-gallon cube to hide the Tunze Streams, I have become accustomed to their size and don't notice them anymore.

Water Parameters:

Water Parameters: Temperature: ~ 27° C Specific Gravity: ~ 1.026 pH: ~ 8.3 (day), ~ 8.15 (night) Calcium: 390 - 420 ppm Alkalinity: 9.6 - 10.0 dKH Magnesium: 1350 - 1400 ppm Sr: 16 - 22 ppm PO4: 0 NO3: 0

I apply most of my time to cleaning the water to provide the fish and corals with low nutrients and clear water. Visitors sometime comment that my fish are "flying in air;" they cannot see the water. Maybe I am unusually strict with water quality, but it works for me.

I use RO/DI water and Tropic Marin™ PRO REEF salt. Kent carbon is used continuously in a 100 micron filter sock. The sock is changed every three days when the carbon (three tablespoons) is replaced. A 39-watt T5 UV sterilizer runs continuously. A Deltec FR509 fluidized chamber with ROWA^®Phos media is used to control phosphate levels. I always use big skimmers with ozone and ORP control. I have the skimmer set so that it produces a wet skimmate and have done this for the last ten years in all of my various tanks. A 10% water change is performed every week. The only additives used are Kent™ Turbo Strontium, Salifert™ Amino Acids and Seachem Magnesium.

Equipment:

This tank was originally skimmed by a Deltec AP850 for the first five months of operation, but I later changed to a Deltec AP902. Currently I am experimenting with a Deltec AP1004 in the setup. The tank has gotten better and better, with less algae and detritus. The real reason for my latest skimmer update is that I am planning to upgrade to a larger tank.

An IKS Aquastar™ computer is my system's "brain." The IKS monitors the tank's temperature, the pH of the kalk reactor, measures the salinity and pH in the main tank as well as controlling the ORP, the lights and top-off water additions. Using a combination of the IKS, some dosing pumps and ancillary equipment makes it possible to have very stable water parameters. To provide calcium and alkalinity to the tank I use a Deltec PF601S kalk reactor and KM500S kalk stirrer. I use A.R.M media in my reactor and E.S.V. calcium hydroxide in the kalk stirrer. The kalk reactor runs at pH 6.5 during the day and 6.7 at night (the IKS controller can have separate day/night parameters). I discovered this provides a more stable Kh over a 24-hour period. I also use a P.O. "dual" chamber containing A.R.M media, located after the reactor, to raise the pH by 0.2 in the return water back to the sump. A chiller? I don't need this in Norway; we have two winters, one white and one green. I also have my sump and equipment located in the basement and this is always cold so I have no problem at all with overheating.

Lighting:

I prefer Giesemann NOVA II lamps and use them because of their compact size. I need two lamps, and with these I also have enough room for four T5 24-watt bulbs. I use Giesemann double-ended 250-watt 14,500 K MegaChrome coral bulbs. The T5s consist of three D & D actinic and one 10,000 K. One of the armatures is dimmable, and I use the IKS controller to run a sunrise and sunset photoperiod.

Photoperiod:

Sunrise starts at 11:00AM with the T5 actinic + 10,000K.
The second bank of T5s (2 x actinic) come on at 11:30AM.
The metal halides turn on at 12:00 noon.
The metal halides turn off at 11:00PM.
The second bank of T5s turn off at 11:30PM.
Sunset starts at 11:30PM and the tank becomes dark at 12:00AM.

Corals:

I only have two large-polyped stony corals. The frogspawn is a fragment from a friend, and I can't wait to see how big it will be after several years have passed. This is the only reason I have a large-polyped species in my tank. My wife and I both like small-polyped species and feel that in a 90-gallon tank the large-polyped species and soft corals would take up too much space, given that we love the small-polyped species so much. We have an extensive variety of small-polyped species; Acropora is our favorite, but we also have Montipora, Pocillopora, Seriatopora, Stylophora and many more.

Today the system contains about 80 different kinds of small-polyped species, most of which were grown from fragments or small colonies. There are roughly 50 in the main display; the fragment tank houses about 30. In a 90-gallon it's very problematic to find the best spot for all the corals, so we have moved them around to find the best place. Also, we often place some of the small-polyped species into the fragment tank for a time. I have tried to find the scientific names of all of my corals, but this is a very big job so today we don't have all of their names. Some small-polyped species, especially Acropora, the vendors also give different names, so I have a kind of Acropora under three to four different names... precise naming is impossible if you don't spend a lot of time trying to identify them.

The only problem I have seen with my corals occurred in February of 2005… red bugs. Many thanks go out to the guys at Reef Central who gave me the necessary help to cure these pests with Interceptor™. Although maybe not truly a "problem," my corals grow out of my tank, but this is a luxurious problem. I also let them grow on the glass so I can move them to a bigger tank later.

Fish:

My favorite fish has always been Pygoplites diachantus. Today, we have two of them in our tank. The first one has lived in the tank from the start and the second has now lived in the tank since February of 2005. They both were acquired from an export company in Bali. Based on information provided by the exporting company, one of them is from the Indian Ocean; the other from the Pacific. The Pacific Pygoplites are colored with especially asymmetric stripes so we are in suspense over how this fish will look with the passing of time. Pygoplites is a very nice fish, but they can sometimes be somewhat reclusive.

For many years I searched for a Zebrasoma gemmatum, but in Norway there are very few places to find fish. Surprisingly enough, while on vacation in Germany, we found this fish and bought it there. When I introduced the Z. gemmatum to the tank, I removed the Acanthurus leucosternon. The Acanthurus leucosternon had lived in the tank from day one, so I was afraid it would kill the new Z. gemmatum. At some point in the future, I will try to introduce my Acanthurus leucosternon again. I also like to experiment with different angelfish to find out if they are reef safe. Although this is a big risk for my corals, somebody must try it to find out. The price I must pay, however, is some wrecked coral tips and periods of the corals' reduced polyp extension.

Feeding:

Daily, we use pelleted Ocean Nutrition's Formula One and Formula Two as well as Kent platinum Herbivore and Carnivore. We also use an assortment of frozen food, which fluctuates based on what the local fish store has available, but we try to vary the offerings so the fish do not eat only one type of food. I want the fish to be healthy so we feed often and in small quantities, three to four times a day.

Other Invertebrates:

We also have four Tridacna crocea and one T. maxima. The T. crocea clams are placed on the bottom of the tank at 75 cm deep. They all have good health and growth even with their deep placement in the tank. There are nine shrimp: four Lysmata debelius, four Lysmata amboinensis and one Stenopus hispidus. I bought only a few snails a year ago, and they have done a good job of controlling diatoms and have reproduced prolifically. I don't have any hermit crabs in the system, and of course, I have seen some algae, but we also find algae on a natural reef. A little bit, I can accept.

For more photos and information, visit Morten's website www.coralreef.no.
All photos © Morten Nordby.

Feel free to comment or ask questions about my tank in the Tank of the Month thread on Reef Central.

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