The Enduraplas 500 Gallon Black Horizontal Sump Bottom Leg Tank is a 1.9 specific-gravity polyethylene tank built to carry heavy ag chemicals and dense liquids that thinner tanks cannot hold safely. It measures 80 inches long by 57 inches wide by 48 inches high and rides on a molded leg base sized for stand or trailer mounting. At a 1.9 SG rating it is engineered for fluids well past the weight of water, which is exactly why it shows up in searches for an Enduraplas 500 gallon horizontal leg tank for chemical and fertilizer work.
Will it work for your load?
Capacity is 500 gallons of black, UV-stable polyethylene. Full of water it carries roughly 4,170 lb; loaded with a 1.9 SG fluid it reaches its rated ceiling of about 7,923 lb (4,170 lb water x 1.9), which is the headroom the 1.9 rating buys you over a standard 1.5 SG water tank. Do not plan on loading past 1.9 SG. Use that max-rated figure when you size a stand, trailer deck, or spreader frame - this is a horizontal leg tank, and the footprint it sits on is 57 by 80 inches. If you are matching tank weight to a chassis or comparing against other sizes, the Tank Sizing Calculator and the Tank Sizing Guide walk through full-weight math for dense liquids. For mobile fertilizer and applicator use, our guide on applicator and leg tanks for fertilizer and the DOT classification of portable utility tanks cover the road-use rules that catch fleets off guard. Refer to the technical drawing on this page for the leg base and outlet layout.
Chemical compatibility
This is a polyethylene tank rated at 1.9 specific gravity, with the resin recorded as HDLPE pending confirmation. Before any chemical service, confirm whether your tank is HDLPE or XLPE and verify your exact chemical at its actual concentration and temperature against the OEM chemical-resistance chart - compatibility is concentration- and temperature-specific. Note that the tank ships without fittings, so the PVC, CPVC, PP, or 316 stainless fittings and the EPDM, Viton, or Aflas gaskets each chemical requires must be specified and ordered separately.
Chemicals this tank handles, with the fitting and gasket materials each requires: Acetic Acid (60%, PP/PVC fittings, EPDM gaskets), Aluminum Sulfate (50%, PVC, EPDM), Calcium Chloride (40%, PVC, EPDM), DEF (32.5%, 316SS, EPDM), Ethylene Glycol (100%, PVC, EPDM), Ferric Chloride (50%, PVC, EPDM), Ferric Sulfate (60%, PVC, EPDM), Ferrous Sulfate (20%, PVC, EPDM), Hydrochloric Acid (37%, PVC, Viton), Hydrofluoric Acid (48%, PP/PVC, Viton), Hydrofluosilicic Acid (26%, PP/PVC, Viton), Hydrogen Peroxide (50%, PVC, Viton), Magnesium Chloride (30%, PVC, EPDM), Peracetic Acid (30%, 316SS, Aflas), Phosphoric Acid (85%, PVC, Viton), Polyaluminum Chloride (PVC, EPDM), Potassium Carbonate (50%, PVC, EPDM), Potassium Hydroxide (saturated, PVC, EPDM), Propylene Glycol (PP/316SS, EPDM), Sodium Bisulfate (PVC/PP, EPDM), Sodium Bisulfite (PVC/PP, EPDM), Sodium Carbonate (30%, PVC, EPDM), Sodium Hypochlorite (under 16.5%, PVC, Viton), Sodium Thiosulfate (40%, PVC, EPDM), Sulfuric Acid (98%, CPVC, Viton), Urea Solution (50%, PP/PVC, EPDM), Zinc Orthophosphate (PP/316SS, EPDM), and Ozonated Water (up to 10 PPM, PVC, EPDM). Match the fitting and gasket to the fluid, not just the tank - a tank that passes can still fail at a wrong gasket. See the full chemical compatibility reference and review fertilizer blending physics in our guide on tank stratification and mixing protocol before you load a dense blend.
The mistake to avoid
Do not put a dense chemical into this tank on the SG rating alone. The 1.9 rating is real headroom, but the resin record here ends in a question mark - confirm whether the tank is HDLPE or XLPE, and verify your chemical at its actual concentration and temperature against the OEM resistance chart before filling. The second trap is the hardware: many of these chemicals demand Viton or Aflas gaskets and specific PVC, CPVC, or 316 stainless fittings, none of which ship with the tank, and standard EPDM hardware will not survive an oxidizer like sulfuric acid or hydrogen peroxide.
This tank ships LTL freight from the Enduraplas plant in Neche, ND, quoted live to your ZIP - get your exact number with the Freight Cost Estimator or call 866-418-1777. Listed price is before freight.
