Rainer,
The Aquacontroller uses it's own language, but you can use any language that can work with serial port communication to get the tank parameters from the Aquacontroller.
With the software I wrote, I was using Java to get the parameters from the Aquacontroller and control X10 modules based on them. I was also saving the parameters to a database for tracking. I was sort of reinventing the wheel since the Aquacontroller could already control X10 modules, but I liked having more control.
When I lost my code, I decided to just use the Aquacontroller's built in programming. I was going to write an interface that would let me change the Aquacontroller program from the web, but Neptune doesn't allow access to the API for updating the Aquacontroller for instability reasons. Only Aquanotes can do the update, which is pretty much why I bought it.