Hello Matthias,

Can you tell me what is PLM-RS232? By the name it is an extension module to have another RS232 port. I was thinking that if you have 2 x RS232 ports then you can connect one Eheim Controller to each port, so you can control two external filters. Please try to put this more clear in the website, it is not clear at all what are the limitations in this moment. I already bought 2 EHeim controllers and 1 PLM-RS232 hoping to control two Eheim filters, but it seems that is not possible. Please try to explain more clear what you can and what you cannot do with your products on the website.

Thank you in advance for your response,
Dragos