Mash tun losses

[tmurph6]

Hey all, I'm preparing for my first all grain brew this weekend and had a question about how to figure my losses from my tun. I have an old 48 qt igloo cooler that I put a cpvc manifold in. I haven't put the slits in the manifold yet, but I decided to see how much water it would take before it started running out the spigot(I took the manifold out to do this obviously). I didn't measure, but I would guess it took at least a gallon and a half of water, maybe 2 before it started running out.

My question is, is this an accurate representation of how much water I can expect to see left in my tun after sparging? I'm thinking to myself that the grain should help displace my liquid and reduce the wort left over, but I'm not sure.

Also, as a side note, my manifold kind of hovers slightly off the bottom of the cooler due to it being made out of rigid piping, is this ok?

 

[wilserbrewer]

The manifold should ideally bend down to the bottom of the cooler to siphon out the last bit of wort. 2 gallons is too much to leave behind.

 

[tmurph6]

What can I use to make this bend?

 

[tmurph6]

I hooked up my manifold. I left 2.5 quarts behind in the cooler. If I wanted to lower my manifold to rest on the bottom of the cooler, can I use a small amount of PVC tubing (siphon tubing essentially) to connect the manifold to the bulkhead? I'd probably just need to pick up some larger tubing from home depot.

Also, is it ok to use PVC siphon tubing on my outlet valve of my tun to transfer my rubbings to the kettle. I imagine yes, but want to make sure.

Thanks!