Main drain, skimmer, and return plumbing

[Titan7]

I have read here it's better to plumb the skimmer and main drain separately to the equipment pad, anyone know why this is recommended?

Returns, how many? Where should they be placed? I have read the wall returns should be about 18" below the water surface. How many on bottom? One of the PB wants to put 4 returns in, 3 on the walls one heat return on the bottom. The other builder puts 3 heat returns on the bottom?

Confused, is there a better design?

 

[bmoreswim]

If the skimmer and main drain are plumbed separately them you can choose to pull from one, the other or both so more flexibility for various circumstances you might encounter during the maintenance of your pool. All plumbing them together does is save the PB a few dollars, but very few.

 

[Titan7]

Thanks, is this a real world issue? Being that I have never owed a pool I don't know the real world pros and cons. No PB I have spoken to runs separate lines for drain and skimmer, one will do it for a pretty big price upgrade.

Any thoughts on the deep water heat returns? 1 vs 3? On the bottom? How many total? Pool is in SOCA, 3.5-5 ft deep.

Was told too many returns will lower pressure and my spa spill over will not work well?

Thank you

 

[bmoreswim]

We spec'd the separate runs but it was also our PB's SOP. So at least one does.