apex questions

[Amadod2]

I been thinking of adding an apex to my tank, I want one to monitor the temp, ph, and I would like to add a water floor detection to it later on. I really do like the mobile interface for my phone. my question is do I need to buy the starter kit or can I buy the parts separately and add them on. I was looking at the junior kit but it only has four outlets and the classic seems to have more things then I need (orp prob etc). so can I but the 8 outlet and the part that controls that?