Not to resurrect an old-ish thread, but I have some questions about master/slave with these pumps too.
When in master/slave mode, do they operate in sync or out of sync? I want to setup two opposing SLWs, but I'd like them to operate out of sync (i.e. alternating). The instructions make it seem like the settings will be mirrored between the 2 pumps (i.e. synchronized). They have the "C" mode which makes them run out of sync, but how do you run that in mater/slave mode?
Ideally, I'd like to just run the master in "Else" mode and then have the other one do the same thing, just 180 degrees out of sync, if that makes sense. I suppose since "Else" mode is just random, I could set both pumps to random independently and just let it roll, but I'd like to only have to mess with one controller for feed mode, etc if possible.