Scrub-A-Dub-Dub

Algae is always an issue at one point or another in every marine aquarist's career, Bryopsis can dominate every surface and choke out anything else, dinoflagellates can seem to be irradicated and by the end of the day the aquarium is full of them, blue green algae can form mats that even cover the substrate! But can algae ever be the solution? Anyone that has had a bad algae problem probably has tested their water throughout this process, and one of the most frustrating problems is that even if your nutrients are out of balance, creating this algae issue, most likely the tests are going to come back relatively positively.

The thing is that the algae that is dominating the aquarium is consuming all of these excess nutrients – and do it so efficiently that it appears as if there is no water quality issue. So how do we compete with some of the most efficient life forms on the planet? You turn them against themselves, algae versus algae and there’s a few effective methods to choose from! The simplest version of this is to just grow certain types of algae in the aquarium that are desirable. Macro algae aquariums are growing in popularity as the saltwater equivalent of planted tanks. There are many different macro algas with different forms and colors to make visually stunning displays that also absorb so many nutrients from the water column that the aquarist will most likely have to supplement phosphate and nitrate to the aquarium at least – and potentially some other micronutrients to ensure that the algae get everything it needs to remain healthy and vibrant. While this method can ensure that nutrients are locked down long term – these macro algas can struggle to outcompete more aggressive things like Bryopsis, hair algae, etc if they are already established in the aquarium.

Starting a new aquarium off with some established live rock that has desirable macro alga already growing on it should help minimize the ugly phase – and many macro algae make great food sources for fishes such as tangs and rabbitfishes. Most of these are easy to acquire. Your local fish store may have cuttings of this – some varieties are desirable enough to be found for sale as well. Otherwise check with other local hobbyists – with the growing popularity of marine “planted” aquariums its more than likely that someone in your area is growing something in their aquariums already and may be willing to share. One of the most common forms of algae as algae control in the marine aquarium is the use of Chaetomorpha alga, more commonly referred to just as “chaeto”. Chaeto is a green alga that doesn’t branch – meaning that it grows essentially as a small tube – circular cells forming long lines that usually curl to some degree and are rigid in texture. It reproduces by fragmentation – small pieces break off and then continue to grow, forming clumps. Chaeto is closely related to cladophora which has feathery branches and is known worldwide to show up in eutrophic (areas of high nutrients) places where it can grow so fast that it becomes a nuisance and can be a detriment to the environment. Chaeto is no different, rapidly consuming nutrients in its environment whether the wild or your aquarium. Chaeto is. usually grown in two different ways for nutrient removal in the aquarium. Since it doesn’t adhere to any substrate it usually doesn’t look good drifting around the aquarium. For those who have sumps small chambers in the sump can be isolated so that Chaeto lightly tumbles in the flow as water moves through the sump. This area will need to be lighted with a light of the right spectrum for algae growth – red and blue grow lights have been used and there are plenty of lights out on the market now specifically designed for algae growth. The faster you grow your Chaeto, the faster you will eliminate nutrients. Chaeto is so popular in the hobby that now days companies sell reactors like media reactors but for holding Chaeto that provide the right light and flow for the algae. For those of you who are into the DIY part of the hobby there are plenty of resources online to replicate one of these on your own as well. Due to how aggressive Chaeto can be, make sure that it is always frozen or boiled before disposing of it. It has established itself in marine waterways in some places and become a nuisance, so do your part to be a good steward and help make sure that it doesn’t spread further.

Algae scrubbers constitute the high-end effort and cost wise as far as algae based nutrient control in the aquarium goes. The premise is that a thin stream of water is trickled over a plastic sheet for needlepoint that can be found at local hobby stores. This is generally abraded a bit to help algae start to cling to it and grow. This contraption is placed in an acrylic box or hung down in the sump so that lights can be mounted with either the plastic or glass between them and the sheet preventing splash back on the lights and algae grows on the sheet. The good thing about this is that the algae that grows in this format are the more aggressive fast spreading algas and they will take over very quickly and then the sheet can be removed and scraped, harvesting the nutrients that the algae sequestered while growing. The sheet is then replaced, and the process repeats itself. Building such a thing can seem intimidating – but nowadays there are a multitude of options as far as prefabricated ones that can just be bought.

In life the old saying "don’t fight fire with fire" is usually true, but sometimes in the aquarium its best to fight algae with algae. It's worked for others, so consider one of these options for nutrient control in your aquarium today. Always remember that algae need to be properly disposed of, so always freeze or boil any algae going down your drain or into your trash just to be on the safe side, keeping our natural places natural and ensuring that different species of algae remain available to the aquarium hobby for generations to come.