Poly Tanks, Steel Tanks, Water Tanks – Plastic-Mart.com Find the Best Selection of Plastic Tanks For You. Home » News » HDPE 4x8 Plastic Sheets » 48×96 pe Polyethylene Storage Solutions - Bestank. Available from 300 liters up to 10,000 liters capacities, there is a Bestank Polyethylene Water Storage Tank for every possible need.