Got a Forest River silverback series that is 39'. model number 35QBH 2013, do not know how plumbing is ran, need guidance as far as if I got two fresh water holding tanks or not. Reason is, when I fill up the holding tank by turning the handle to get gravity flow to fill up the tanks, I notice that looks like I got a drain port that is emptying out but another drain port right next to that is not cause its has a plug on it. Do I have two fresh water tanks? Also I've got two flush valves for the black tank, but one is leaking on the valve, possibly that it has back pressure? Don't see crack on it or anything that looks like its busted. Also notice that I have a low point drain as well, and it leaks out as well. But where is it coming from. Its on the other side of the 5 th wheel, not where all the plumbing is for drain ports. Just need some guidance if anybody has the same year and model number. I appreciate it.