Therefore we've started structuring our processes lately. The daily and weekly checklists are meant to make maintenance measurable, our logging interface provides a tool to collect water data. For our tidy set of water tests we use brand new test tubes. We write down when and what we plant and how much we harvest. We're even making plans for a collection of photographs of leafs so we hope we can determine nutrient deficiencies in the systems. Take a look at this tool, still in beta, to see our data collection: Graph tool. Some graphs are not yet filled very much, but pH for instance is a nice one to look at.
Granted of course we're not scientists, this can help us back up the 'feelings' we have about running an aquaponics system.