The Hydros can control dosing pumps. In fact Hydros has a dosing pump you can connect to one of the drive ports on the Hydros. The Hydros and the Apex are both controllers. It is the way they to about it that makes them different. The Apex has a central brain you add modules to to control and monitor different things. The Hydros every module is a controller in itself with the exception of the wifi strips and wifi plug. So each module can be a individual controller on its own or in a collective they act together like one larger controller. On the Apex if you loose the brain you are out of action until you get it repaired or replaced. With the Hydros if you loose a controller you only loose the inputs and outputs from that controller but the collective won't happy and you will get a lot of alerts because of it. All other functions that don't need the inputs or output on the lost controller will continue to function as they did. You can also set the output on controller to either remain on or turn off if a input that is needed is unavailable. If you want you can just use it for monitoring things and sending alerts if things get out of the range you setup. They sell a monitor only version of the X3. It is the same X3 it just does not come with any outputs but you can get either a wifi strip or a XP8 to add them when you are ready to start controlling things with it.I want to make sure I understand completely, so sorry if I sound a little 'dumb' here but I'm new to this. So a Hydro basically is the same thing as an Apex? Can the hydro be set up to also monitor say like ALK/MAG, etc? Can you also add a doser to it? Or is the Hydro just for basic monitoring and plug control?