The Solinst 425 Discrete Interval Sampler collects a groundwater sample from one exact depth without mixing it with water from other depths in the well column. Before lowering, the stainless-steel sampler body is pressurized through its tubing so water cannot enter it. It is lowered on a suspension/safety line to the exact target depth, then the pressure is released (vented). A floating check ball inside the sampler body (PTFE ball, which sinks, at the bottom; polypropylene ball, which floats, at the top) opens under hydrostatic pressure, filling the sampler with water from that specific interval; re-pressurizing before retrieval reseals the balls so the sample stays isolated on the way back up. At the surface, a separate Sample Release Device lets the operator decant the sample in a slow, controlled stream by pressing its stem into the decanter body, minimizing agitation.

Do you have everything you need? The 425 requires a Solinst High Pressure Hand Pump (sold separately) to pressurize and release the sampler, plus a reel sized to the tubing length in use. Replacement parts and reels are available in the Solinst 425 Discrete Interval Sampler Parts & Accessories collection.