Notes:
• If you are deploying trays in pairs place them side by side, around 30–50 cm apart (or
as convenient).
• Always deploy the trays with the numbered tag at the upstream end. For ease of
recognition (and to allow for correct orientation of trays from photographs) the
upstream end is also marked with brightly-coloured paint. As a further check, mark the
nutrient rows at the upstream end of the inner plastic frame (N, P, N+P, C) with an
indelible marker pen.
• Numbers 1–20 are systematically assigned to the jars. Always use these numbers as
part of your labelling system for the containers into which you collect the filter papers,
for example, site no. (or letter) + jar number.