hello
i am electronics engineer, i have long experience in prototyping work, adding sensors like PH, temp and conductivity, is so easy the algorithm gonna be as this, firstly we need to certify the controller how will collect the data from the sensors in the water tank, then we compere this reading with reference reading which is saved inside the microcontroller, then the desgin will have ability to control the pumps,heater...etc
we might recommend some new ideas about your project during the conservation,
we have a long team, team which able to work with you and travel at you to solve any prototyping problem, we take a consider at the price its will be low according to prototyping works,
we can make a deal with you, and we have stander platform for android application and web service, so hopefully to send us either here or by email