Biofilter for aquaponics: The biological filter, or biofilter, is a key component in the filtration portion of a recirculating aquaculture system (RAS). The biofilter houses the nitrifying bacteria and is the primary site where biological nitrification occurs. Common dish scrubber pads can also make excellent biofilter material. Download fact sheet at link.
How to grow strawberries vertically with a PVC pipe support system. The instructions on this site are well-written. No heating/re-molding of the PVC pipe is required. PVC pipe can be painted. Lightly sand the pipe, paint with primer (Kiltz or Zinsser 1-2-3) to cover up any writing on the pipe and seal it, the spray with plastic spraypaint (Krylon Fusion).