Anybody have the extra fresh tank option on their Momentum?

[Luv2Ski]

We have the 2017 328M with the 2nd fresh tank option. Looking at the underbelly, I have two fresh tank pull drains and two overflow drains as expected. There is just 1 fresh tank fill on the Nautilus panel in the utility bay and no other fill points that I can find. There is only one fresh tank level indicator in this rig (yet I have 2 black tank indicators and only 1 black tank - go figure).

Can anyone answer the following questions?

1. Are the tanks tied together at their low point so they fill in parallel or does one fill and then overflow into the other? Note that if I plug the first overflow when it starts gushing water, I can fill for about 15 minutes before the other begins to drop water.
2. Are these tanks vented to the roof or are the overflows used to vent air during filling?
3. Which tank is the fresh level indicator indicating?
4. Is it normal that my indicator only reads 3/4 tank when the first overflow starts gushing water?
5. Are the overflows attached to the tops of the tank or the sides?
6. Is one tank shorter than the other thereby preventing a full fill of the taller tank?
7. Where does the water pump draw from the tanks? Or is it just from one tank?

[Dave and Monica]

As the additional capacity is optional, I believe that the system would be designed to operate without it, ie the venting and drains are separate, the tank filling and supply to the pump is piped to the main tank as well as the level indication. The additional tank must be connected in parallel to the main. I think your testing/observations answer some of your questions. The 40 gal optional FW tank can't be the same height as the main 117 gal tank or isn't installed at the same height as it's probably the one that overflows first yet you still have additional capacity shown by level indication and your testing. To know for sure you can call the GDRV Customer Support line @ 574 825 9679 and they should be able to answer your questions.

Dave

[Luv2Ski]

Thanks, Dave. I drew up a way I think might work better than what I have now (whatever it is), but assumed the tanks are the same height and are level (i.e. only the widths are different). That's probably not the case though