Choosing Sampling Pumps for Hydrogen from Deep Wells

The Grundfos Redi-Flow II will cause major problems - it generates hydrogen. In fact, any pump that puts an electrical current down-hole can (and likely does) cause the same problem. An air-actuated bladder pump (e.g. QED) will work, but the problem is the surging - you may get the average flow to 300 mL/min, but while the bladder is emptying the flow can get very high, so you need to either:

1. Pump out of the well into the bottom of a five gallon bucket and use a peristaltic pump to pump out of the bottom of that bucket into the sampler. NOTE: Pump the purge water into the bucket first so there is a thick layer of well water between the atmosphere and the sampled water.

2. Adjust the stroke times of the pump to get it as near continuous as possible. Excessive surging do not affect the analytical result, it simply makes sampling impractical by causing the top to pop-off or the bubble to exit from the cell. As such, simply using the cell is a sufficient test.