When we had our HW27KS, I made a connection that allowed me to attach a regular sewage hose to the grey tank valve. There’s a long thread somewhere on here about the parts and parts numbers. I don’t have that info.
Sorry for the poor pic quality, but I think you get the idea. This allowed me to connect like you see in the other pic. Sometimes I would just connect one sewer hose and switch between valves as I needed to dump.
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