Why do so many fish die? Simply: running any fish tank is very complicated. A successful fish tank requires constant monitoring of everything: PH levels, Nitrates/Nitrites, & temperature. If any of these measurements get out of whack, prompt corrective action is needed to prevent further deterioration.
Eric Maundu at Kanji Grows has been working on a wireless control system that automates the measurements and corrective actions required to maintain a high performance aquaponics system.