Newbie help with schematic, leaks and levels!

[freeflynick]

I am about to fire the Pool Guy and start doing the work myself, and would appreciate a little guidance.
If the schematic loads up, does it look like I have things labelled correctly - I gave it my best guess!
I have a few other Q's:
My pool and spa both have two drains and the pool has two skimmers. From the (hopefully) attached schematic, do each of these pairs Tee into one line for the return to the pump/filter?
I have a lot of air going into the hot tub with the blower switched off - is this a sign of a leak somewhere, and if so, where is a good place to start looking, and how is a good way to find air leaks?
The hot tub level has started to drop over night - roughly leveling out with the pool level. There is also a leak around the "overflow" coming out of the selector valve on the filter inlet/outlet. Could these be related, and again, what are good troubleshooting steps to find the root cause?
Thanks for any help you can give.
Cheers,
Nick

 

[freeflynick]

Here is a photo of my setup.....

 

[jblizzle]

The 2 floor drains connect together. Likely one of the pool suction valves is the floor and the other is both skimmers (one would be plumbed to the bottom of the other skimmer).

I am not sure why you would have 2 spa return lines with 2 check valves if that is what you are indicating.

Usually a blower is not required for spas if plumbed correctly. It is not uncommon for there to be air pulled in through the blower even with the blower off.

The draining spa is likely due to one of the check valves on the spa return line.

The "overflow" is the waste/backwash line. There should not be any water coming out of that unless in Waste or Backwash mode. If there is, that would point to a leaking spider gasket, but have nothing to do with the spa draining.