Galvanic backfill is used with either magnesium or zinc sacrificial anodes to provide an environment which is conductive for anode dissolution.

The chemical backfill helps to retain moisture around the anode, lowers the anode-to-earth resistance, thus ensuring good contact between the anode and soil and providing a uniform environment that reduces self-consumption of the anode.

The typical galvanic backfill mixture composition consists of:

• Benjamin Franklin Gypsum: 77% ± 2% (for low resistivity);
• Wyoming Bentonite: 15% ± 1% (for moisture retention);
• Sodium Sulphate: 8% ± 1% (for prevention of polarization).

• Supersacks of 2200/2400 lb (998/1089 Kg);
• Bags of 50 lb (22.7 Kg), 56 bags/skid;
• Custom packaging requirement.