ya the PVC to PVC was my only issue, I think I just needed to be more liberal with the Weld-On, also It was my first sump glue up and I didnt have anyone helping me hold and clamp. What I ended up doing to fix the leak was just run a fillet of Weld-On on the inside seam.Looks like the leak is pvc to pvc. Nothing around the acrylic windows? That’s where my concern would be. Disimular plastics don’t bond well together. Hope the silicone works especially with that rabbet cut into the pvc. Flexing, due to water pressure might cause separation with time. I am following because I make acrylic sumps. Another thing, don’t know if you looked into a 1/2” white acrylic sheet and cost as compared to PVC sheet.
This would solve your bonding issue.
I believe the PVC flexes more although it is easier to cut.
I am actually not concerned at all about the acrylic viewing panes, I know that Silicone isn't great at attaching to either PVC or Acrylic, but the silicone was on the cut edges of both where there should be plenty of grip, combined with the rabbit and the fact that the water is pressing the acrylic into the pocket.