The Enduraplas 400 Gallon Black Horizontal Leg Tank (SKU THF00400B) is a low-profile haul tank built for moving water and a wide range of ag and water-treatment chemicals down the road and across the yard. The black polyethylene shell carries a 1.9 specific gravity rating, which is what lets this tank legitimately haul dense fertilizer blends and acids rather than just water. It measures 37 in high, 46 in wide, and 74 in long, so the integrated legs keep the center of gravity low for trailer and skid mounting. Buyers searching for an Enduraplas horizontal leg tank in black land here for exactly this combination of low profile and heavy-duty rating.
Will it work for your load?
Sizing is where leg-tank buyers get surprised, so run the real numbers before you mount it. Filled with water this 400-gallon tank weighs about 3,336 lb, but at its full 1.9 SG rating the contents alone can reach roughly 6,338 lb. That difference matters: your trailer, frame, and tie-downs have to carry the heavier number if you ever fill it with a dense chemical, not the water figure. The footprint is 46.0 x 74.0 in, so confirm your trailer deck or skid has that much clear, supported area underneath. Run your target volume and weight through the Tank Sizing Calculator and the Tank Sizing Guide before you commit to a mount. Fitting configuration varies by build, so confirm outlet size and bulkhead locations with us before ordering, and refer to the technical drawing on this page for the leg layout.
Chemical compatibility
This is a black tank rated to 1.9 specific gravity, but the resin record ends with a question mark, so confirm HDLPE versus XLPE with us before you put any chemical in it. Resin and crosslinking determine what a poly tank can safely hold, and the 1.9 SG rating gives you real headroom for dense chemistries. Most water and ag blends never need it, but of the chemicals below, concentrated sulfuric acid (98%) and ferric chloride (50%) are the kind of heavy liquids that justify the 1.9 rating over a standard 1.5 tank. Always size fittings and gaskets to the specific chemical, concentration, and temperature using the OEM chemical-resistance chart.
One callout for the high-demand DEF crowd: this tank handles DEF at 32.5% with 316SS fittings and EPDM gaskets. DEF (urea solution) demands clean, stainless-only wetted metal — no carbon steel, no brass — or the urea corrodes the hardware and contaminates the fluid out of spec. The same stainless discipline applies to peracetic acid (316SS fittings, Aflas gaskets), and the aggressive acids run Viton rather than EPDM: hydrochloric, hydrofluoric, hydrofluosilicic, hydrogen peroxide, phosphoric, sodium hypochlorite, and sulfuric. If you are specifying hardware, do not default everything to PVC/EPDM.
Chemicals confirmed compatible with this tank's resin and SG rating, with the recommended fitting and gasket materials, include: 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). Verify your exact concentration and temperature against the OEM chemical-resistance chart, which is concentration- and temperature-specific. Browse the full chemical compatibility reference for anything not listed here.
The mistake to avoid
The single most expensive error on a leg tank like this is mounting and tie-down rated for water weight when you plan to haul a dense chemical. Plan your trailer and restraints around the 6,338 lb rated-contents number, not the 3,336 lb water weight. And because the resin code is still flagged HDLPE versus XLPE, confirm the exact resin with us before any chemical service, even when the chemical itself appears on the compatible list above.
This tank ships LTL freight from the Enduraplas plant in Neche, ND, and we quote freight live to your ZIP. Get your number from the Freight Cost Estimator or call us at 866-418-1777. For application context on horizontal leg and applicator tanks, see our guide on applicator and leg tanks for fertilizer, the breakdown of portable utility tanks and DOT classification, and the deep dive on fertilizer-blend tank stratification.
