The Snyder Industries 550 Gallon Captor double-wall tank is a black, high-density linear polyethylene vessel built for full secondary containment in one footprint - the primary tank sits inside an integral outer wall, so if the primary ever weeps, the spill is caught instead of hitting the ground. It measures 76 inches wide by 76 inches long and stands 65 inches tall, holds a rated 550 gallons, and is built to ASTM HDPE construction. With a 65-inch height and a square 76.0 x 76.0 footprint, confirm door and header clearance for your building before delivery. If you are weighing this Snyder Captor double wall tank against a single-wall tank plus a separate basin, the Captor stack collapses two parts into one self-contained black tank.
Will it work for your site?
This double wall tank is rated to a specific gravity of 1.9, which is the heaviest contents weight the structure is designed to carry. Plain water has a specific gravity of 1.0, so at 550 gallons full of water the tank carries roughly 4,587 pounds of liquid; at the full 1.9 SG rating the structure is engineered for up to about 8,715 pounds of contents. That spread is the reason to pay for a Captor: the 1.9 ceiling gives you real headroom for dense fluids that would over-stress a standard 1.0 to 1.5 SG water tank, while still catching any primary-wall weep in the outer shell. The trade-off is that you must match your actual fluid's specific gravity against the 1.9 ceiling before you fill, and remember the usable volume is not the nameplate 550 gallons once freeboard and thermal expansion are accounted for. Use the Tank Sizing Calculator and the Tank Sizing Guide to confirm the working volume and weight for your fluid.
Fittings and access
The factory configuration on this tank includes a flange, an 18-inch polyethylene threaded and vented fitting, and a manway with 15-inch access for entry, inspection, and cleanout. The vented 18-inch fitting lets the headspace breathe during fill and draw so you do not pull a vacuum or pressurize the dome. Source your mating hardware to suit: the flange connection needs a matching gasket, and the 18-inch PE threaded port needs thread sealant compatible with your stored fluid. See the technical drawing on this page for the exact fitting locations, sizes, and elevations, and confirm each port against your piping plan rather than assuming standard placement before you plumb the inlet, outlet, and vent.
The mistake to avoid
The common error on a Captor double-wall purchase is treating the 1.9 specific-gravity number as a free pass for any fluid, or assuming the nameplate 550 gallons is all usable - both can put you out of spec. Because this is HDPE, any chemical or dense-fluid service also means verifying that your stored fluid is compatible with the resin and that its specific gravity stays at or below 1.9; a "water" rating is not blanket approval for every liquid. Read Snyder Captor Double-Wall Freeboard Sizing per ASTM D1998 and HDPE Tank Wall Thickness at the Vapor-Saturated Headspace before you size. If the install is for spill containment under federal rule, the SPCC 40 CFR 112 compliance walkthrough covers how a Captor fits the requirement, and for remote water storage the fire-water reservoir design guide walks through NFPA 22 sizing.
This double-wall tank ships LTL freight from the Philippi, WV plant, with the rate quoted live to your ZIP code - get your number from the Freight Cost Estimator or call 866-418-1777 to lock in delivery. Have your ZIP and delivery details ready and we will quote the freight on this 76 x 76 black double-wall HDPE tank.
