last year we weren't able to, because the Ipad itself wasn't capable of split-screen.  It may be now, but we ended up using my brother's cheapo chromepad for the liquid monitoring system and the Ipad for fieldview.  Lotsa screens in the cab, but at least we didn't have to buy anything new.  I wonder if even a iphone or android phone could run the liquid monitoring app?  It might be worth looking into if you don't want to buy anything else, and those all have wifi.