Thinking Of Setting Up A Marine Aquarium? Read This First.

Both marine (saltwater) and freshwater aquariums are incredibly beautiful and rewarding to keep, but they are very different in both their biological and physical setups as well as the level of maintenance required.

If you’re a beginner, it may be better to start off your hobby with a freshwater aquarium, which will be much less demanding and will carry lower maintenance costs. However, if you feel ready to move on to a more complex marine aquarium, there are a few things you need to take into consideration before you take this very exciting plunge into the Big Blue.


The cost of setting up and running a marine aquarium can be significantly higher than those of running a freshwater aquarium. These costs are split into three main areas:

Initial costs of marine aquariums – Setting up a marine aquarium from scratch is generally more expensive than a freshwater aquarium, and this is mainly due to the need for additional equipment and, in some cases, a larger tank. We will run through the equipment needed for a saltwater aquarium in just a moment, but this expense is worth bearing in mind in the meantime as you’ll need to buy a lot of equipment in one go.

Costs of marine livestock – Once you’ve acquired all the equipment you need, there is still the cost of the livestock to consider. Marine fish species are some of the most intriguing and beautiful in the world, and a more expensive method of catching and stocking them is required. Therefore, it makes sense that they will carry a higher purchase cost than freshwater fish. This is especially true if you are looking to set up a reef aquarium, as the cost of live rock and corals is high due to their delicate nature.

Running costs of marine aquariums – The cost of running a fish-only marine aquarium isn’t all that different to that of a freshwater aquarium, as it is generally a case of a little more electricity useage for the additional and slightly more powerful equipment. If, however, you’re looking to run a reef aquarium, the running costs will be much higher due to the need for additional air pumps and significantly more power-consuming lighting.

Equipment for Marine Aquariums

If you already keep a freshwater aquarium you’ll be familiar with a lot of the basic equipment needed, however you’ll notice a few new additions that are specific to marine aquariums.

Aquarium – The obvious first port of call is the aquarium itself. You can usually choose between acrylic and glass aquariums – acrylic gives you more choice in terms of aquarium shape, but can also be more expensive. Whichever material you choose, we would recommend you choose a larger tank than you would for a freshwater aquarium, as larger tanks provide a more stable environment due to the water chemistry changing more gradually.

Lighting – Marine aquariums, particularly reef aquariums, require specialist marine lighting to ensure healthy growth of corals and other livestock. These light units provide the necessary light spectrums for the level of photosynthetic activity that is essential for keeping your aquarium inhabitants alive.

Substrate – You can choose whether or not you want to include live rock as part of your substrate, or if you want to start with non-living substrate. Whether you choose to include live rock or not, sand is a good substrate to use as a base as this is the most naturally occurring material found on most ocean floors.

Filter and Protein Skimmer – As with all fish tanks, you will need a quality filter to keep harmful ammonia and nitrite from building up. We would recommend a more powerful, external filter for a saltwater aquarium, particularly if you have a larger tank and the available storage space to spare.

A protein skimmer should also be used in conjunction with your filter, and will help lighten the load on your main filter by removing organic compounds from the water before they break down into nitrogenous waste.

Powerhead – This is an essential piece of kit for marine aquariums with corals, as it simulates the natural reef currents of the ocean. Powerheads provide a steady stream of ocean-like current and help with the development of your corals if you’re setting up a full reef tank.

Heater and thermometer – Depending on the types of fish you’re looking to keep, you may need a heater and thermometer to replicate and maintain ocean conditions. Make sure you research the needs of your fish, coral and live rock to determine the required temperature.

Hydrometer – In a saltwater aquarium it is essential to monitor the gravity and salt levels in your water. A hydrometer is a simple and elegant solution, and will sit in your tank to give you continuous readings.

Sump – This isn’t an essential piece of equipment but is handy if you have the space. A sump is a separate, smaller tank that sits below the main tank which acts as an alternative to an internal or external filter system and is also a great place to keep your heater and skimmer out of sight.

Marine Aquarium Maintenance

Maintaining a saltwater aquarium is a bigger time commitment than maintaining a freshwater aquarium, as the system is much more complex and sensitive.


Ideally you should be monitoring various aspects of your saltwater aquarium on a daily basis, particularly the water temperature, performance of filters and skimmer, and the general appearance of your fish and coral. You should also keep track of salt levels on a daily basis using your hydrometer.


On a weekly basis you will need to test the water quality including pH, ammonia, nitrite, nitrate and phosphate levels using a test kit. Your weekly tasks should also include cleaning down the glass or acrylic panes of your tank to keep algae at bay, and vacuuming your substrate.

Bi-weekly and monthly

You will also need to perform partial water changes every 2-3 weeks for sparsely populated tanks, or every week for heavily populated tanks, to prevent buildup of harmful substances and lighten the load on your filtration system and skimmer. Frequent, smaller water changes are more beneficial than larger, infrequent changes, which are more disruptive.

It may sound like a lot of equipment and work, but keeping a marine aquarium can be incredibly rewarding, and is just like having your own miniature ocean. If you can spare the time for the research and maintenance, keeping a marine aquarium can be a very exciting hobby, and we’d love to help you set yours up.

If you’d like any help with finding equipment for setting up a saltwater aquarium, simply give our sales team a call on 01642 612419 and we’ll help you get started.

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