Backyard Aquaponics
A place to discuss aquaponics

make a wood frame(relly good wood frame) that will hold up to the water pressure and order some liner.
should be able to get it shipped to anywhere.You can make any size you want and do it inexpensive
all it takes is ingenuity

Isn't there any fiberglass workshops around you. You can probably get something build to your specifications which will outlast you.