The Tube Holder is a piece of hardwood that sits directly beneath the tubes (holding their weight) and has holes for both the air injection tubing and the RGB LED lights for each tube. I made it out of hardwood because I had to drill 120 holes in it, and because it would be screwed to the tube support upright which is MDF.

The tolerances for the holes are relatively small, so I was careful in measuring, marking, and drilling.

Every inch a 1/2″ spade bit was used to drill a hole for the air tube, and then between them a 5/16″ bit was used for the RGB LED light.

The final product looks very regular: