The sump tank is the lowest point of the aquaponics system. The water in the plant beds drains to the sump tank and then a submersible pump forces the water up into the fish tanks and back to the plant beds. If the submersible pump stops working all the water in the drains to the sump tank and the water level rises. This is not a normal occurrence for this system and could indicate a pump failure. A sensor can be used to alert the staff if this happens.
A battery powered arduino detects the level of a float switch and will send a message to Plivo. Plivo is a text messaging service (currently costs about 1/3 of a penny per text message). If this situation occurs the phones of the staff will be sent a text message immediately.