Field Facts and Findings
We have experienced in the field that rarely is the water and microbial growth near the fill end of the UST’s. Most of the contamination is found near the probe and pump areas of the tanks. Because of this microbial growth around (the quite area) where the ATG probes rest, the effects of this is many false monitor readings. We have inspected and cleaned tanks that the monitor read 1 ½ “inches of water and have found very little water. On the other hand, we have seen monitors that have read 0”inches of water and have removed 50 to 150 gallons of water and bacteria.
After we pull up the probe and clean around where the probe rests and clean the probe itself of sludge and bacteria, we then get accurate readings from the monitors. Because monitors read 0” inches of water, it does not mean the tank is free of water. A good percentage of tanks we have inspected have been sloped to one side or the other and have removed a great deal of water from these tanks. Monitors can only read or detect water if there is water around the probe, the monitors we have seen do not detect water at the ends of the tank.
There have been times where we are called to a site to clean tank bottoms because of slow flows and frequent filter changes, but because of the lack of regular tank maintenance and tank bottom inspections the sludge has accumulated so much that the sludge becomes very dense or calcified. In these situations the tank owner needs to have the tank physically cleaned by way of manned entry. This can cost the owner many thousands of dollars to have this type of service performed.
Optic Fuel Clean of CA recommends to have UST’s and AST’s inspected and cleaned at least once annually to prevent the effects of water and microbial contamination.