You can use it stand alone. I slowly converted to Hydros from the Archon starting over 3 years ago. To begin with I was passing signals between them using relays. The inputs on the Hydros were sense ports where I would connect the switch inputs to the analog input on the sense port. I used switch inputs on the Archon. It would depend on the relay what output I used to drive them. So there can be simple signals sent between the two controllers if needed. If you want to use the test readings for dynamic dosing you can use the two drive ports to run a couple of simple dosers as long as you are dosing a large enough amount each dose. For smaller doses Hydros has a 2ml per minute dosing pump but it is AC powered but you could add a XP8 to the Maven and create a collective and you would have 8 AC outlets you can control with the test results. Creating a collective requires a bus cable to connect between controllers and a minimum of 1 terminator but 2 is better and will be needed for larger collectives. The terminator is a resistor that is needed to allow communication between the controllers on the command bus which is a CAN type bus system. They also have wifi power strips and outlets but those require wifi communication between the controller and the power strips to be commanded on r off so if communications is lost the outlets will remain in whatever state they are in until communication is restored. For that reason I do not recommend using them for dosing, ATO or AWC purposes.As with others, I have substantial sums “invested” in Apex. But solutions like this particular product might just be the catalyst for me to switch over. The design appears practical and the addition of NO3/PO4 sadly is important for me due to my feeding patterns. Very interested!