Algae Grow Workflow

I created an LED light fixture and air tubing system to culture fresh water algae for feeding daphnea and other filter-feeding organisms.

Food Web Aquarium Mindset ​

My reason for growing algae is that I want to keep various interesting aquatic life in my aquariums without making these creatures suffer under my care. Algae is the foundation for this.

I love aquariums, but currently keep only plants and one very old parrot cichlid because I’m increasingly disturbed by the treatment of animals in the hobby. To truly thrive, animals require the correct habitat and food, amung other factors, all of which should be stable over time. To reliably provide the highest quality diet, the whole food chain should be built from the bottom up.

A food chain begins with the autotrophs, of which algae is the most foundational in the aquatic ecosystem.

Therefore, in order to keep higher trophic level animals such as bivalves, crustations, and fish, I need to first culture algae so I can feed those animals correctly. The algae will not be the direct food source for many of these animals, but rather the food source for the food source. There are multiple trophic levels to traverse before we can keep certain animals.

Growing in Jars ​

Jars are an good container for growing algae because they are made of glass, inexpesive, readily available, and easy to handle for harvesting and cleaning. Glass is the a desireable material because it is transparent, chemically/biologically intert, hard wearing (resists scratching), and easy to clean.

Lighting from Below ​

The core concept behind my design was to light the algae grow jars from below.

Lighting from the top wouldn't work well, because the lid of a jar is at the top, as well as the air entry points, and these would block the light if the light came from above.

The light could come from the side, but then a fixture would be needed to hold the lights at the correct level, the light would spill sideways illuminating the surrounding space in a possibly undesirable manner, further exasturbated by the cylindrical shape of the jars, which would bend and magnfiy the light dramatically.

Lighting from below gives the light a clear path into the jar through the flat bottom, and points the light away from the surrounding space. It also looks really cool because the light source is hidden.

Parametric Lid Generator ​

I used 1/2 gallon jars but didn't have enough lids, plus the lids I had felt too thin to support the air tubing and hold it vertical in the jar.

I decided to 3D print my own jar lids but didn't want to pay for Fusion360 just for that simple modeling task, so I made a parametric jar lid generator.

Air Supply ​

The jars require airflow to supply the algae with oxygen and to keep the water well mixed so that the algae remain suspended and evenly exposed to light, oxygen, and nutrients.

To supply air I used a small aquarium air pump with a loop manifold of 1/4 inch vinyl tubing. The loop ensures that pressure is equal at all of the exits tees.

Despite the loop, a valve is still required at each exit to equalize the pressure. Without the valves, air will flow into one jar but not the others.

For the valves and fittings, I used push connect fittings.

For the tube entering the jar, I used a ridigd piece of 6mm OD polycarbonate tubing. I found that 6mm OD tubing is compatible with 1/4 inch push connect fittings.

Greenwater ​

To start my culture, I purchased a half gallon of greenwater on eBay.

It cost $30.80 shipping included.

Feeding ​

To feed the algae, I simply add a small pinch of blue crystal plant fertilizer. There is a noticable explotion in growth after I add the fertilizer.