Setting up a Marine Tank- The Basics

Setting up a Marine tank.
by Shawn Published on 20-04-2009


Setting up a marine reef aquarium may seem like a daunting task, but is fairly easily achievable provided you follow a few steps.

Select the area of the house where you want the tank to be.

Buy the largest aquarium that will fit in your space, or the largest aquarium your budget will allow. Larger aquariums provide a much more stable environment, because the water chemistry will be easier to maintain over time.

A good rule of thumb is that a reef aquarium will end up costing twice what you think it will.

It is better to choose a tank that is not too deep(e.g. 24 to 30") so you can reach the bottom easily; a tank that is wider will provide a better depth of view for a more natural look. A second smaller tank (a sump) is often placed under the main aquarium and will hold all the equipment out of sight.

Choose lighting: Metal halide lamps provide the best lighting for most of the corals commonly kept, other forms of lighting are also obtainable and offer varying degrees of success. 250 watts bulbs will suit most common aquariums except for the deeper ones where 400 w bulbs provide more light penetration.The color spectrum of the bulbs (expressed in color temperature in Kelvins) is a matter of personal preference. Bulbs between 6500 kelvin and 20000 kelvin are the most popular, and the higher the kelvin rating the 'bluer' the color. Some claim coral growth is affected by the color, but corals grow fast and successfully on either end of bulb 'spectrum'. One halide bulb for every 2-3 feet of tank length is usually recommended.

Other types of lights to consider are florescent lighting, specifically high intensity fluorescents. Two popular kinds are Power Compact and T5. These can be found in many of the same color ratings as metal halide bulbs, and are much cheaper. A popular choice is to use both florescent and metal halide. An aquarist will use a single color of metal halide, like 10000k, and will use a few blue (or Actinic) fluorescents to make the color more pleasing.


Set up the filtration: Get a good quality protein skimmer and place it in your sump. Do not skimp on this. Often protein skimmers are under-rated for the size of tank, so in practice a skimmer rated for a 100 gallon tank is barely adequate for a 50 gallon reef tank (especially one with many fish that get fed a lot). Needle wheel skimmers are a popular choice, and can be very effective for their size/cost. Don't rely on 'venturi' skimmers, unless they are high end models with very strong pumps.

Don't bother buying 'canister' filters, often used on freshwater aquariums. Not only are they fairly useless in a marine aquarium environment, they can even cause a buildup of Nitrates on their internal media that can negatively effect the aquarium. Bottom line is they are a waste of money.

Adjust the flow. Now is time to get a saltwater rated pump to return the water from your sump to the main tank. Additional powerhead pumps in the tank or external pump(s) should be installed to provide additional vigorous turbulent flow, which is crucial to the survival of your future corals.


Place a heater(s) in your sump if you have one.
Some people consider using an aquarium chiller. The high intensity lighting used in reef aquariums adds a surprising amount of heat to the aquarium, making it harder to keep a reef aquarium 'cool' enough. Even in San Francisco, where the avg. temp is around 68 degrees, its easy to overheat an aquarium on a warm day. If you have hot summers where the temp in your home goes above 80 degrees F, you will overheat your aquarium.

If required, fill the tank with tap water partially then totally to test for leaks. Run all your pumps.

Prepare enough artificial seawater for the volume needed. Use only a good aquarium sea salt brand and purified water with a Reverse Osmosis or R0/DeIonization Filter. Another option is to fill the tank with RO/DI water and then add the salt. The importance of RO/DI system cannot be understated.
Tap water is simply not suitable for reef aquariums. A good RO/DI system is not too expensive, and should be considered a necessity. A 100 gallon per day model is a good choice, because you won't have to wait too long to make purified water which is a nice convenience.

Once you mix your saltwater and fill your aquarium, turn on all your pumps and let the water 'rest' for a day. It takes a little time for your salt to dissolve and your water chemistry to stabilize, and the action of the pumps will drive out excess carbon dioxide (which initially causes a low pH).

Add 'live rock' and arrange to your liking, approximately 20% of your volume. The rock can be placed on an aragonite sand bed but the substrate will tend to accumulate detritus overtime. A sanded depth of 4 to 5" is recommended for maximal detritus biological processing. Live rock can be obtained online or at your local marine aquarium store. The sand bed has to be placed before the seawater is slowly added.

Let the tank "cycle". This means you will need to wait until the water tests negative for ammonia or nitrite. Inserting bits of frozen fish foods in the sand bed can speed the cycle. (This is unnecessary if you added live rock. There are plenty of dead crustaceans and worms already inside due to shipping).

This may take 1 to 2 weeks. Algae blooms can be a natural part of the cycle. Check and make sure the salinity is stable at 1.023 to 1.026. Compensate for evaporated water losses with RO/DI water. Keep the temperature, Calcium and Alkalinity levels stable. Do not use commercial "supplements" other than water changes.

Algae blooms are common for probably the first 6 months of your aquarium, so don't be alarmed to find new algae growing.

Add cleaning creatures such as snails, small hermit crabs and finally herbivore reef fishes.

Many aquarists feel its not proper to being adding corals until the tank is a few months old. A 'mature' tank is much more suitable for growing coral. A good rule of thumb is to watch your live rock. At some point, you will notice the rock 'growing', and not just green algae. You will seen new crustaceans, worms, feather dusters, coralline algae, and more. When the algae blooms subside, and the live rock is growing nicely, its finally time to add your coral.