How to build build a VIRTUE rack

The rack is built by placing a pair of CD-shaped plastic discs back-to-back (composed of PET-G) with fixed distances of 10 cm between each pair. We recommend using 5 sets of discs per rack. When the discs are retrieved out of the water, it is easy to examine the upper and lower sides because it consists of two separate discs.

Supplies for 4 VIRTUE discs:

  • 4 x 10 transparent plastic discs (with a center hole)
  • 1 VP/PVC pipe with outer diameter of 10-12 mm (length is usually 300 cm if you buy in electrical stores)
  • 1 VP/PVC pipe with outer diameter of about 16 mm (length is usually 300 cm if you buy in electrical stores)
  • 8 pcs of cable tie (available in hardware stores)
  • 1 white, plastic sign
  • Rope (syntetic 4-5 mm, enough length for the specific place) and weights (could be almost anything).

How to use:

A mounting instruction is included in "What is growing on the disc?" (download as pdf).

If you order kits from the VIRTUE team, a construction instruction is included.

Swedish VIRTUE participants can order complete kits for VIRTUE racks. To order the material, you must have signed up for VIRTUE. You can do that directly on the site. Then order the rack via the VIRTUE order page. If you order kits from the VIRTUE team, instructions are included.

Schools outside Sweden can send a request to We can provide you with information where to buy the components. In the future, we hope to establish VIRTUE hubs abroad that will be able to provide teachers in their country with VIRTUE kits free of charge.

A plastic sign may be included in each kit. (If so, the sign must be reused!). If not, find any white, durable plastic sheet, cut into square signs and drill a hole for the rope. The sign must be fastened well above the water surface.

Enter contact information, date, location and "ID number" for the rack.

Use a pencil (preferably hardness 2B or 3B) - pencils adhere best on plastic surfaces and the text is easy to remove.

A QR code linked to VIRTUEs web site can be applied on the sign. You can easily create your own QR code.