We have a 2018 353TS which I suspect is very similar to your 351. On ours, there are 2 gray tanks, 2 black tanks, and 2 drain lines. However, note that they drain in an odd (to me) way. The forward drain handles the forward black, forward gray, and rear gray tanks. The rear drain only handles the rear black tank.
Here's why I mention this; we have found that the forward gray tank catches water from the main bath sink & shower plus the kitchen. It fills up rapidly (compared to the other tanks) due to showers and dish washing. You can quickly find yourself with this one tank full and not a great deal in the other tanks. The rear gray tank handles only the sink in the 2nd bath - it gets very little use.
Solution: If you leave the cap on the forward drain line, you can open the dump valves for both the forward and rear gray tanks and "bank" them together. Doing this gives you 41+41=82 gal of gray capacity. The down side: close the valves on both gray tank drains before you pull the cap! In our case, I installed 3 inch "last chance" valves at the end of the drain line where I connect the drain hose. This allows me to "bank" the gray water and still make a connection with the drain hoses before dumping. I always close the gray valves, then dump and flush the black tanks, then use the gray tanks to "flush" the dump hose last.
Just a thought...
|