The Chem-Tainer 390 gallon open top batch storage tank is a rectangular polyethylene reservoir built for batching, mixing, and bulk water staging where you need full top access to load, monitor, or service the contents. It measures 66 inches long by 42 inches wide by 33 inches tall, and the entire 42 by 66 inch top is open for loading, cleanout, and mixer-shaft access. It is molded in natural white polyethylene rated to a 2.0 specific gravity. If you have been searching for an open top tank, a rectangular open top tank, or simply a rectangular tank that sits low and stable, this is the open tank size that fits a 42 by 66 inch pad.
Will this tank work for your job?
With a 390 gallon capacity, a full load of water weighs roughly 3,253 pounds, and at the tank's 2.0 specific gravity rating it is engineered to carry contents up to about 6,505 pounds. That 2.0 rating gives you roughly twice the water-weight margin, so you can batch denser liquids such as brines and slurries up to a 2.0 specific gravity at full volume without derating, which is a real difference from the 1.0 to 1.5 specific gravity water-only open tops. The footprint is 42 by 66 inches, so confirm your pad or containment area accommodates that low, wide stance. For batch control by sight, the geometry works out to roughly 12 gallons per inch of fill (approximate, based on 390 gallons over the usable height), which makes dosing and level checks easier in an open top. Use the Tank Sizing Calculator to check that 390 gallons matches your batch volume and turnover, and the Tank Sizing Guide if you are sizing several stages of a storage train. The technical drawing on this page gives you the exact bottom and wall dimensions for layout.
Mounting and the mistake to avoid
The most common mistake with a low, wide open top tank is setting it on an uneven or undersized surface. A rectangular tank of this footprint needs continuous, level, full-bottom support; an open top design has no structural lid to tie the walls together, so uneven bearing or point loading is what stresses the corners over time. Pour or verify a flat pad before filling. Plan your emptying method up front, too: a flat-bottom open top tank retains a heel and has no gravity-drain cone, so size in a bottom bulkhead fitting or a pump-out if you need to empty it completely. For above-ground polyethylene installations, our concrete pad sizing guide walks through the ACI 360R-10 framework for getting the bearing surface right. If this tank feeds a reuse or aggregation system, the industrial water reuse tank topology guide covers how to band quality and sequence storage stages, and for emergency-water staging the fire-water reservoir design guide covers NFPA 22 sizing discipline and freeze protection.
Freight
This tank ships by LTL freight from the Chem-Tainer plant in West Babylon, New York, and freight is quoted live to your ZIP code. Get an exact number with the Freight Cost Estimator before you order, or call 866-418-1777 and we will quote the lane and confirm lead time. Because this is a low, wide open top tank, it is a stable, easy-to-handle freight item, but the rectangular footprint still ships as a single rigid unit, so the delivery ZIP and dock or liftgate access drive the rate. Listed at the price shown before freight.
