Congrats on your new rig! Most trailer manufacturers install the flooring on the flat trailer deck before any walls are started which makes it tricky to repair subflooring and covering. Check with the manufacturer for advice on how to go about making repairs. Almost positive the pink stuff is antifreeze, it isn't poisonous but will make the water taste terrible for things like making coffee or cooking. Run it through with normal usage and it should clear up after a while. It is probably in the fresh water tank too, so be sure and use the pump or drain the fresh tank and refill.
2004.5 GMC SLT CCLB, Ride Rites, Turbo brake, EFI Live
2012 Arctic Fox 29 5T 5th Airborne, B&W, Prodigy
Papillon navigators Lily, Buddy and Willow