Plumbing Question

Chances are you will need a couple different size hole saws and bulkheads as return lines are generally smaller than your drains. Your return line will depend on the size of your return pump outlet. I would think 2 - 1" drains should be enough as you shouldn't need to have more than a few hundred GPH flowing through your sump, based on a 45 gallon display. Any upgrades to flow within the display tank won't effect your overflows. source

You very likely have a legal case against the contractor. I would suggest you begin documenting everything. Yes, get a camera inspection and get 2 or 3 plumbers to give you their opinions and advise. I would also suggest you discuss this with an attorney ASAP to get his advise on the procedures you need to do. You want a solid, well documented case if and when you go to court. source

The dip tube is made of PVC or plastic might be just starting to deteriorate and causing your problem. This has been me experience when troubleshooting Dishwashers with a no fill problem on a few occassions. source

Understand how you feel, but as the plumbers need to dig holes and draines all over the places to lay the pipes, it's definitely not safe for them to work in such wet condition... As it's a long process, just calm down and be patient... source

Other thing you will need to remember is that these days, most, houses have their plumbing on the inside of the walls. So I would have thought that many grey water diverters would need to be on outside plumbing? source