Macroalgae tanks

Hello from Seattle, Washington. My name is Dennis and I go by tigahboy.h2o on Instagram. I started keeping saltwater reef tanks back in 2004 and have maintained mostly nano and pico reefs since then. I’ve always found the freshwater planted scape aesthetic very appealing and wanted to try to replicate that in a saltwater tank, so I started my journey into the world of macroalgae with my first macroalgae-dominant tank (or planted reef) back in February of this year. Since then I’ve created two additional macroalgae tanks, all inspired by freshwater planted tanks. I also have a new macroalgae project in the works, so stay tuned for that.

There’s not a lot of resources on macroalgae keeping available, so I’ve had to learn as I go, through trial and error, and have sought input from other macroalgae keepers I’ve met on Instagram as well. I’m still learning, but I’ve found macroalgae keeping to be very enjoyable and exciting. The diversity in colors, shapes, and textures found in macroalgae is truly remarkable and I think rivals the beauty of other coral reef tanks. Needless to say, I’m hooked on macroalgae!

Here’s some info about my tanks:

1. Lagoon Mixed Macroalgae Tank:

Tank: UNS 60S
Volume: 10 gallons (35.1L)
Dimensions: 23.62″ (60cm) x 14.17″ (36cm) x 7.09″ (18cm)
Light: Twinstar 600S – full spectrum planted tank lights
Filtration: Biological filtration from over 20 lbs of live rock and macroalgae itself of course. Also run an internal filter box to surface skim with filter pads/floss.

Inhabitants: 14 different species of macroalgae, branching coralline algae, and red mangroves. I also have a pygmy red rooster waspfish, two blue sapphire damselfish, 2 peppermint shrimp, and a variety of snails and hermits. I wanted this tank to have a variety of colors while my other two macroalgae tanks have focused more on a specific color (red for my UNS 45A and green for my UNS 16C).

2. Red Macroalgae-dominant Tank:

Tank: UNS 45A
Volume:9 gallons
Dimension: 17.71″ (45cm) x 11.02″ (28cm) x 11.02″ (28cm)
Light: Twinstar 450E – full spectrum planted tank lights
Filtration: I have bio media in here to supplement the live rock, but no other filtration aside from the macroalgae itself of course.

Inhabitants: 6 different species of macroalgae, but I try to have red macroalgae dominate this tank. I also have 6 masked gobies, 3 sexy shrimp, and variety of snails and hermits. I wanted this tank to have mostly red macroalgae, and gracilaria hayi is the predominant red macroalgae in this tank.

3. Halimeda Pico Cube Tank:

Tank: UNS 16C
Volume: 1 gallon (3.8L)
Dimension: 6.29″ (16cm) x 6.29″ (16cm) x 6.29″ (16cm)
Light: ONF Flat Nano LED
Filtration: no filtration other than the live rock and macroalgae. I have a HOB filter on this tank, but that’s just for circulation.

Inhabitants: This tank only has halimeda. I used it to create a carpeting effect. I wanted to keep this tank minimal with green as the primary color.

All of these UNS tanks are made by Ultum Nature Systems based in Los Angeles, California.

Additional Insights:

1. When keeping a macroalgae tank, you can keep it very simple in terms of filtration. No need to run a protein skimmer or a lot of filter media such as carbon or phosphate removers since the macroalgae would benefit from the extra nutrients. The macroalgae keeps the water very clean and crystal clear. They also outcompete diatoms, so you won’t have to worry as much about diatoms when you keep macroalgae.

2. A lot of reefers think keeping macroalgae is very easy, but keeping up with their nutrient demands can be challenging. I dose fertilizer, ferrous iron, phosphates, nitrates, in addition to calcium and alkalinity two-part solution to keep my macroalgae thriving.

3. In order to keep red macroalgae a nice deep, red color, it’s actually better to have lower intensity lighting and dosing ferrous iron helps as well.

4. When keeping macroalgae, there’s always a risk that the macroalgae can go sexual and release spores into the water as a last-ditch effort to survive by reproducing somewhere else. If you are keeping coral, the release of all the excess nutrients back into the tank could be detrimental, so I suggest keeping carbon on hand in case this happens. Keeping enough nutrients, trace elements, and stable parameters will help minimize the risks of macroalgae going sexual. But it is still always a risk. If it happens, just remove the dying macroalgae, do a big water change, and run carbon. The key is to act fast.

Dennis

What was the measurement data on the day of our visit?