If your boat was winterized by sucking pink antifreeze through the exhaust system, then pink would be in the heat exchanger. I think that is what you drained. If so, it will fill up next time you run the engine and the impeller forces raw water in there.
The two hoses between your HX and hot water tank is a closed loop of engine antifreeze--now that you need to top up because I assume you lost some antifreeze when you replaced the hose.
2000 Beneteau 331
Northern Chesapeake Bay
Ambition is a poor excuse for not having enough sense to be lazy ~ Steven Wright