DIY sump - using heavy duty crates?

[Ky_acc]

Anyone have any thoughts or concerns about building a DIY sump using heavy duty crates similar to what’s show below?

I’d plan to connect them with bulkheads and pvc and use probably 3 in a row

They are made out of polyurethane and can support 175lbs.

Quantum 24" x 15" x 9 1/2" Heavy-Duty Gray Stacker Straight Wall Container with Built-In Handle Grips RSO2415-9

The Quantum 24" x 15" x 9 1/2" heavy-duty gray stacker straight wall container with built-in handle grips makes keeping organized easier than ever! Boasting an injection-molded high-density polypropylene construction and reinforced corners, this tub is extremely durable and can withstand the...

www.webstaurantstore.com

 

[KrisReef]

I actually think these are made to stack, which might make connecting them (standpipe overflow) easier if there is any advantage to going up. I have basically a "Tupperware" sump for my reef, holds water and doesn't rot.

 

[redfishbluefish]

I just don't know what they are made of.....

You stated polyurethane in the OP and the link, in the body of the text, they say polypropylene, while the table summary along the side says polyethylene.