Well Wizard Bladder Pumps: The Original, Low-Flow Sampling Standard. Well Wizard pumps for MicroPurge low-flow groundwater sampling systems come in an unsurpassed range of sizes, materials, and capabilities, including models for deep sampling wells, narrow or obstructed casings, and small-volume pumps for low-yield monitoring wells. Together with MicroPurge controllers, flow cells, and accessories, they create the most reliable, cost-effective low-flow groundwater sampling system available. Field proven pump designs and an exclusive, high-performance PTFE bladder formulation offer the reliability critical to long-term monitoring.