Macroalgae aquariums are not only awesome because of the unique and cool-looking inhabitants, but also because they are fairly simple and affordable to set up and maintain. Affordability all starts with the equipment you decide to use because this will be a majority of the initial cost.

You always have options when it comes to rock, sand, and other equipment and you can most certainly choose a tank size and various equipment based on your particular budget. If you have leftover gear from a previous tank build, even better! 

Remy's Macroalgae Bundle

To make things easy, we put together a tank bundle, Remy's Display Refugium Start Kit, that includes all the components used in this particular tank build. Don't worry though, should you decide to choose your own adventure or use some equipment you already have, we have got you covered too!  Just take these tips and useful insights into mind when choosing the main components for your tank and we are confident your tank build will go smoothly.  

Choosing The Right Tank

Remy chose the AquaMaxx 9.1 gallon Cuboid tank because it's a modern rimless style tank, has low iron glass, and won't break the bank. Of course, the available space you have and the final location of the tank in your home ultimately play a significant role in terms of the tank size and shape. This long-rectangular shape provides a nice wide viewing pane and lends itself well to an interesting aquascape.

You can choose any tank you like, traditional plastic-framed tanks will work just fine and are generally really affordable at local fish stores. You can go as small as 2 gallons or as large as 100+ gallons. Just keep in mind, bigger tanks are always going to cost more both upfront and when it comes to maintenance. You will not be needing a sump or any complicated plumbing and you don't have to use an AIO style tank either, just a simple glass box will do the trick.  

You do want to take into consideration your goals for the tank too. What do you want to keep inside?  Tall and leafy macroalgae? Maybe fast-growing coulerpa? What kind of fish or creatures and how much space will they need?

Aqua Illumination Prime Freshwater LED

Lighting For A Macroalgae Tank

Macroalgae is photosynthetic, it requires high-output, full-spectrum lighting to thrive in an aquarium. This is awesome because it means algae feed itself (for the most part) using nutrients from the aquarium, ultimately providing the primary filtration or nutrient export.

For this AquaMaxx 9.1 Gallon tank, the Aqua Illumination Prime Freshwater LED light is the perfect choice. The flexible mounting arm will attach securely to one of the ends, positioning the light over the middle with enough spread to cover the entire tank.  The AI Prime family of lighting is one of the best values and most widely popular LED lights on the aquarium market and comes highly recommended by both our customers and our staff. 

The best choice for spectrum (color of the output) is going to be white daylight (6,500K - 10,000K) LED light-exactly what is used on freshwater planted aquariums. This will compliment the natural colors of your macro and other tank inhabitants. While purple or blue/red colored refugium LEDs might push the macroalgae to grow a bit faster, most of us prefer to have a bit better viewing experience than all purple all the time in our display.

Macroalgae Tank

**Pro Tip: White daylight makes for incredible pictures using your phone or camera. You won't need any gel filters or special software to capture natural-looking colors in the tank.

Alternatively, you could technically use a reef tank LED light, which typically has a heavy blue spectrum along with white, but you would want to tune the light to operate with a heavier white spectrum for better viewing meaning you might end up wasting some of the power. I would only consider this if you're using a light you already have on hand.

When it comes to output there is certainly a range. Macroalgae tend to be pretty hearty in terms of surviving in a wide variety of conditions, but if you want the macroalgae to thrive, stick with a high-output LED.

Macroalgae can shade themselves and their neighbors quickly so having an effective light spread across the entire tank will be ideal. Either a pendant or a long panel style LED will work out great, you can even consider some strips lights like the Tunze, Orphek, or Reef Brite.  

Water Flow

Water Flow

Whether you're using a hang-on power filter or simply a powerhead, you will want some internal water movement. Macroalgae tanks DO NOT NEED a filter because the algae itself filters the water and you can easily perform necessary water changes should the nutrients get out of hand. That said, using only a small powerhead to move the water will work just fine, but a hang-on power filter is a better option so you can add media like a filter sponge or carbon down the road. 

Remy chose the Seachem Tidal Filter which was made specifically for saltwater tanks, it has adjustable flow and gives you plenty of space for filter media should you find the need for it. 

Aquarium Heater

Most macroalgae available in the reef aquarium hobby are tropical and require a water heater to maintain temperatures of 75° - 78°F.  The BRS Titanium Heating Elements are among the highest quality aquarium heaters you can buy, especially when combined with an InkBird WiFi Temperature Controller which allows for easy programming and remote monitoring.

3-5 watts per gallon of aquarium water is the general rule for choosing an aquarium heater in terms of size or wattage.  You can lean towards higher wattages to ensure you have enough power and reduce the necessary heating time. With smaller tanks like this, it's not a bad idea to oversize the heater slightly.  It will heat up faster, reduce the on/off cycles, and generally have an easier time maintaining temperature.


Rock & Sand

Caribsea is hands down the leading substrate brand. When it comes to sand, just choose something you like in terms of appearance. We generally recommend that you avoid really fine grade sand to reduce the risk of creating a sandstorm with your water pumps or when cleaning the tank. Dry or Live sand will work and Remy chose the Caribsea Arag-Alive Special Grade Reef Sand which happens to be the most popular choice among hobbyists. Live sand contains live beneficial bacteria right in the bag, it does not require rinsing before use and will help initiate the cycling process in a new aquarium.

You can use our sand bed calculator to find out just how much sand you need! 

Caribsea also offers some gorgeous purple-colored rock they have dubbed LifeRock. The facts are, any of the available reef rock options will work just fine. The colored rocks simply provide you with a more natural-looking aquascape right out of the gate, you won't be stuck with stark white rock.

Choose enough rock to build whatever kind of scape you're looking for with anywhere from 0.5 - 1.5 lbs per gallon being the norm. Remember Macroalgae needs room to grow and many species will grow quickly so don't fill the tank up with too much rock.  If you want to keep multiple types of macro, it may be a good idea to create islands in an attempt to isolate different species. Being the algae generally grows upwards or creeps outwards over the rocks, a lower-lying scape with plenty of large surfaces for planting will be able to support a thick forest of macroalgae. Ultimately, the macroalgae are going to fill in a majority of the scape so use that to your advantage, the rock in this case is simply a foundation.

Macroalgae Tank

Macroalgae Supplements

In order for a macroalgae dominant tank to thrive, you will need nutrients along with a variety of minor and trace elements that the algae will uptake as it grows. The three following Brightwell Aquatics bottles will give you a comprehensive dosing solution, especially when the algae starts to take off.

If your keeping a population of fish or other animals in the tank, their waste and leftover foods will provide some level of nutrients too so monitoring nitrate and phosphate with a water test kit can help you determine how much you need to dose. If you're curious to learn more about dosing nutrients and trace elements in a macro tank, check out the related video links below.