Started winterizing my boat today. 2006 Crownline 250CR w/Merc 5.7. Got the poo tank emptied out and put 1 gallon of AF in the head and pumped until it was empty but thinking I need a little more than that? I was planning on running the macerator to get pink in the thru hull line and seacock. I'm sure there is probably a little waste still left in the bottom of the tank so thinking a few gallons on AF would be better? Filled the fresh water tank and added 1/2 gallon of bleach and let it set for a few hours. Ran that through all the faucets (cabin, bathroom, cockpit sink and transom shower). Bypassed the water heater but drained it and opened the bypass to add a little pink to it. Used 1 gallon in the head and 3 gallons in the fresh water. Is that normal? Planning on buying another 5 or 6 gallons this week to add to the head and fresh water and to do my AC. I bought a drill mount pump and plan to run the AF into the thru hull and back to the AC thru hull intake. Figuring 1 gallon for that? Also bought 7.5 gallons of the AF with corrosion inhibitors for the engine but haven't got that far. Going to order one of those Camco winterization kits today to do the engine. I store underground in a mine that never goes below 55* but this past year it was 20* the week after we pulled our Sea Ray out of storage. I had always winterized it too but just drained everything and left it empty. So about how much AF should I go through? 1 engine, AC, fresh water tank (about 30 gallon), 6 gallon water heater but bypassed, no gennie and the head with macerator? Figuring not including the engine I will go through about 10 gallons but at ~$3/gallon I'd rather be safe than sorry. Next question...there is a well (or sump) under my cabin step with a bilge pump and float. There is also a plastic box with 3 hoses going into it. 1 appears to be the shower drain, 1 seems to be the bathroom sink, and not sure what the 3rd is unless it is an outlet? Anyway, this box has a clearish lid and I can see that it is full and leaking out around the edges into this well. What is the purpose of this box? Is there a pump inside it? If there is then mine must not be working? That 'well' that it sits in doesn't appear to go anywhere. I don't see any drainage holes or anything in it so it just sits there and fills with this water until the pump kicks on?