Plumbing Help with sump/pic

My new sump 24" is not far off being put in its final resting place, it has 3 compartments, where as my old 15" long only had 2, this opens up a whole new load of possibilities and with it how to plumb it,
I have attached a picture of what i propose, any ideas or suggestions would be much appreciated,
I have till thursday until my tank gets changed over

 

Is the skimmer going into the left chamber ?

 

Very confused by this^^^^^^^^^^
what is an emergency return?Why is there a valve on the main return??

 

Yes sorry skimmer will be in left chamber

The emergency return is the back up standpipe incase the main standpipe gets blocked and the ball valve on the main return is so I can restrict flow back to the sump if I desire to do so

 

The overall layout looks good, though I'm no expert. So the ball valve is to prevent water from syphoning back when the return pump goes off? You can also drill a small hole just below the water line in the return pipe in the tank. That would break the syphon. Also, not sure how close to scale the drawing is, but it doesn't look like there is much room for extra water. Just my two cents.

 

You never want or need a valve on the main drain. If your overflow is set up correctly, the drain flow will match the return pump output and the DT water level will remain constant. Restricting flow to the sump will end with a flood.

 

The easiest way to prevent a flood is to make sure the return in the tank is high enough so that it comes out of the water and breaks the siphon without overflowing the sump.

 

Maybe i should give more specifics,
The weir is a 3 standpipe, 1" left return will stand 6" high with maybe a durso
above the sump this is attached to a ball valve and returns as in the picture

middle is 3/4" return, the pipework that carries the water back into the tank has been split at the top so it returns the water to the left and right

And the right standpipe(backup incase the main overflow gets blocked), will be 6" higher then the main return 12" high

all connections just prior to the bulkheads have a union connector fitted or stop cock(ball valve) as on the return, for ease of dissassemble

The pipework came with the tank the ball valve was already attached and used at the lfs like this, so to save time and money i thought i would use it to?
Correct me if im wrong but does the herbie method use a ball valve to restrict the flow from the return just enough so that the water returns down both standpipes?

 

This.