Dometic 300 Fresh Water Leak

[bigmurph]

This weekend we went camping for two nights. Both nights were in the mid 20's so I unhooked the city water and used the fresh water tank and pump overnight. When we were packing up and getting ready to leave my wife turned on the bathtub to drain the fresh tank down before heading home. We had no leaks all weekend but when she finished emptying the fresh tank she noticed that the toilet had some water around it on the lower area where it bolts to the floor/flange. I came in and checked and there was a drip hanging off the foot pedal. At first I thought it must be the valve but we couldn't make it leak again when we got home. That made me wonder if there is a vacuum break on the toilet that might have leaked when the pressure got low? I'm not a plumber but I have noticed that my vacuum break for the black tank flush will sometimes drip a couple of drops when you first hook it up so I thought maybe when the pump/tank was running out of fluid it could have had the same problem. Probably not though. So now I must decide, do I replace the valve and keep an eye on it or upgrade to the 310. Decisions, decisions. If I do try the valve replacement first, does anyone suggest one brand vs another? Are they all the same?