75 gallon sump build -- how does it look?

[ReefingHavoc]

Building my first sump. Dimensions are 48x18x20 constructed out of 1/2" acrylic. I'm modeling it after a Trigger Systems Triton design with a large refugium (section 2).

Flow will move from left to right (1-4) with an external pump being plumbed in. Section 3 will house my skimmer and section 4 will have an egg crate shelf in the first bubble trap section for a bag of media (carbon). I'll be adding clear covers to reduce evaporation. This will be a basement sump so I'm looking to make sure there is plenty of space for water to drain if power goes out (120 gallon on first floor).

Looking for input on the layout:

• Is there enough room in the return chamber? There's about 4" between the last baffle and the outer wall -- total size = 6.5"x17"x8"
• Should I keep the bubble trap?
• Any other thoughts or recommendations?

See attached for pics


Thanks!