If we have wells that sit idle for a period of 15 days or more, and the water flow through the well is NOT significant, throughout, the well should be treated with “Layup Chemistry”. Simply calculate the volume of water, and for every 10 gallons of water, add ¼ lb. of sodium bicarbonate – not caustic soda or soda ash, just sodium bicarbonate.
It is best to pre-blend the water and the bicarbonate above ground, then flood the well with it. If gradient water flow is a problem, direct application of the powder can be trickled down the well in hopes some will reach the bottom of the well. Stagnant water is a breeding habitat for bacteria. With the presence of sodium bicarbonate and water, their breeding appears to be suppressed.
The durability of the layup chemistry is limited to gradient water flow, water temperature and other factors. We would suggest we/us consider a semi-annual assessment.