Step 3: The Tubes
I wanted to use a closed loop system where the algae would travel constantly and safely without getting contaminated, so using clear acrylic tubes was the best option.
I initially wanted to use 15mm outer diameter tubes with an inner diameter of 12mm in order to carry the water required to grow the algae, as well as to match the pump power (4000 Liters per hour) that I had obtained for a previous model. However I quickly realized that at every return point of each tube there was no silicone or plastic based hose that was flexible enough to bend around to each connection point.
This wasn’t all disappointing as it meant that I could downsize to 12mm outer diameter tubes with an inner diameter of 8mm and save on cost at the same time. Unfortunately even though I moved down to that size, finding a hose which would fit on the outside of the 12mm seemed impossible.
That is when I decided to try to enter the 8mm inner area of the tube; something considered very unconventional and ‘inconvenient’ but to me this was the only option as far as flexibility was concerned with the materials available to me. I found a 8mm outer diameter silicone tube and it fit perfectly inside.