An improved optical sensor and method for measuring concentration of a chemical constituent where measurement interference from other chemical compounds is present in the solution is provided. The management architecture includes interfaces configured to the entire electronics and mechanics to provide a parameter to a computer. The invention further relates to planting dwarf lettuce seed at a high density in the field and harvesting dwarf baby leaf lettuce leaves over a longer period of time than that for non-dwarf conventional lettuce. In order to create a desired dispersion of the solids within the potted termination, a new potting process is employed, whereby the strands are wetted with liquid potting compound before the anchor is placed over them. The invention further relates to a hinge for use therein. The ID element is embedded within object elements of the 3D object.