New to is mysteries

[bucky]

Our new to us 2014 Forest River Blue Ridge 3025RL has 2 mysteries I need some help on. There were no manuals in the unit when we bought it last week.
This unit has a fresh, gray, and black tank. There is a door on the road
side behind the propane door that contains a gray and a black tank pull handle along with other plumbing controls. The mystery is that about 4 feet back on the skirting is a round access door that unscrews and accesses a third pull handle that is labeled as the other gray handle is. The fresh drain is clear back by the rear bumper on the road side. Anybody know what and why that is there? No second BTW and all specs on the web list only one 60 gallon gray tank.
The other mystery is the factory speaker system. There are 3 speaker choices and all can be on or chosen by themselves. A is the living room roof speakers and C is the storage bay fold down speakers on the curb side. B plays music but the speakers are inside the road side living slide somewhere which makes no sense. There are no grilles inside or outside on the slide (open at the time) and they sound like they are serenading the refer. Just curious on this question.
Thanks for any guidance.

[JAC1982]

Yup ours has the two valves for gray similar to how you mention. We did not know this the first time we went to dump, and the one further back was open... that was quite stressful, especially since we didn't know if it was gray or black at the time.

[bucky]

Thanks guys. Unit is listed as 1 60 gal gray but we all know how RVs and especially waste tanks go.

[edbehnke]

if you have 2 pull handles you have 2 grey water tanks. Close one and run water from your sinks and you'll figure it out

have no idea about the speakers.

[mooky_stinks]

My trailer is listed at 60. Which is 2 30 gallon tanks.

[lee_worsdell]

It could be a kitchen grey tank drain handle . my montana has the same thing one pull handle all by itself