i have a recently purchased ericson 25 which has a holding tank. it looks to be in generally good condition, but has an interesting (strange, actually) feature. the intake hose to the head leads from the holding tank. this seems illogical as i'm going to be pumping the eventual sludgy water back into the head as flush water. i showed this to a couple of guys at the dry dock area and they thought it was unusual. one person suggested i cut a through-hull and route the hose from there to the head, therefore having a continual fresh water water flush supply. the only logic i can see to having my head system set up this way is that you aren't faced with an overfilled tank at some point. therefore...it's time for a pump out when you're fainting when you flush???i'm leary to set and use the head yet for what should be obvious reasons. if anyone can explain why a holding tank is set up this way, i would appreciate it. thanks matthew