Help with sump
 

Can someone explain the logic on these partitions before I rip them out. From the right they're on 17,21,26 and 30" centres.

looks like it's for baffles but i don't know how you would get a under overeffect.

Planning on changing for a bubble trap made of three baffles one inch apart next to the skimmer, then another baffle on the left next to the pump intake, keeping an open area in center for DSB.

That looks like your standard Bow Valley sump to me. The idea is that you cut pieces of egg crate or something to fit into each gap and in the space provided you can put sponges, carbon or whatever. Works pretty good if that is something you need to do.

Getting those chunks of glass off will be difficult. Unless you need to change it, don't.

Planning this, only concern is flow over DSB.

Id suggest makeing your pump chamber larger.
When you turn the pump on youll loose all the water that goes into the plumbing from that chamber.
Along with your daily evaporation. So unless your planning on a auto top off.
You'll end up having to top it off all the time.

I agree. Even with auto top-up, I am a firm believer in a large pump reservoir for peace of mind.

It's definitely going to be bigger. Guy that did the drawing for me was working off a napkin. Number was 16 inches out for a volume close to 10g