Nothing spoils the enjoyment of a marine tank more than brown slimy water. Not only can you not see your beautiful fish and corals properly, but it is a sign that the tank is unhealthy and your livestock could be at risk. Here are some of the reasons that the water may have become brown, and how to tackle it.

 

Algae

Algae growth is one of the main culprits for turning clear water brown. Unfortunately, if you are a first-time fish keeper, you might find that your pristine bright tank is exactly the kind of environment algae thrives in. There are several different types of algae; some will grow on the glass, and can be removed with a scraper.

Nuisance algae growth is the kind which pollutes the water, making it appear cloudy and discoloured. If left untreated, it may eventually affect the oxygen balance of the water, and suffocate the coral. It can be controlled by adding a marine clean up crew (CUC) to your tank. A CUC should consist of a variety of critters, as they will all eat different types of algae.

Hermit crabs will graze on algae and uneaten food in the tank, and add to the interest of your livestock as well. There are several species, so make sure you choose a reef safe variety. As they grow, they need larger shells provided for them, otherwise they may attack other crabs or snails and steal their shells.

Nassarius, or Nas, snails are useful for keeping sand on the bottom of a tank fresh, because they burrow and turn it over. They won’t eat algae, so you will need to provide extra food for them. However they will eat dead fish or other snails. Algae grazing snails, such as the Turbo and Astrea, will graze on fine algae, particularly on the sides of the tank.

Sea hares are a type of sea slug, and will hoover up hair algae bloom very efficiently. However, once all the excess algae is gone, they are at risk of starvation. Therefore, you should only consider this type of critter if you are an experienced aquarium keeper, or if you are able to loan one for a short period only.

Emerald crabs are an important part of a CUC, because they will eat nuisance bubble algae, plus other types algae and uneaten food. Therefore, add up to three of these crabs if you have an average sized tank.

 

Keep up tank maintenance

If your water is still discoloured despite adding a CUC, make sure that you keep up with the routine tasks, such as changing the water, and removing rotting organic matter and floating debris. Check the Ph levels and chemistry of the water on a regular basis, to make sure that you have the balance right. Make sure your filter and pumps are clear and running correctly.

Before adding any new substrate to the tank, make sure you wash them first to remove any potential contaminants.