Using refugium algae to control nutrient levels in your reef tank
It is interesting how few people understand the true benefits that can be achieved with a refugium. Algae can sometimes become unsightly in a “show reef” setup. Yet, the aglae benefits the aquarium by removing excess nutrients and elements that would otherwise buildup in your reef tank. Using a refugium, algae can be grown in a separate tank and fed sparingly to your show tank to provide sustenance to grazers.
A refugium is simply a refuge tank that is connected to the main aquarium. This secondary aquarium acts as a refuge, allowing species to be kept that would otherwise be unsafe, or unsightly in the main aquarium. Refugium algae can let you have the benefits of fast-growing macroalgae without having it ruin the appearance of a show tank.
The purpose of growing algae in a refugium is twofold: it will remove any extra nutrients from the water, and can be harvested for feeding of any grazers in your main aquarium. For you to receive the benefit of this refugium, algae must be able to grow quickly. This means its needs must be met in abundance. The nutrient requirements are already taken care of – they are in excess and ready to be absorbed by the macroalgae. The refugium must have plenty of light to allow maximal growth of the algae and any other plants. This means you need to consider the placement of your refuge tank. If it is hidden under the main show tank, there must be access for several long fluorescent tubes.
Once the refugium is setup, you need to seed it with the various species of macroalgae that will take up residence there. Various red, green, and brown species can be used this manner. If you are just starting out growing your first refugium algae, consider using chaetomorpha as it is great for this purpose! Chaetomorpha is excellent at removing both phosphates and nitrates, and does not undergo sexual reproduction in the aquarium which would release the nutrients back into the water, potentiating a crash! You should know, however, that not many herbivores will consider eating this type of string algae.
So, if you find yourself having problems associated with nutrient levels being uncontrollable, consider setting up a refugium – it can make all the difference to the water quality in your show tank.