Check with your parish coop. ext. agent they can usually help . You can also use hydrated lime or potassium permanganate to sterlize small water pockets. The later link (KMnO4 ) I would leave to the pros. See links below.

Liming to Sterilize http://edis.ifas.ufl.edu/FA028

Potassium permanganate http://edis.ifas.ufl.edu/FA032