Looks great! I haven't seen drain lines entering the sump with slotted pipes like that before. I'd be interested to know how it works for you. If your standpipes have a flushing problem when you fire up the system I'd suggest the loops in the flex pipe as prime canidates for the cause. Any loops/dips in the line tend to build up air and the flushing effect is the purging of the air which causes the typical burping of large bubbles in the sump. Best to prevent air from building up in the first place.
G'Luck with the tank.
G'Luck with the tank.