Measuring the Scum Level
This procedure is for determining the distance between the bottom of the scum layer and the bottom of the outlet baffle or tee.
- Establish a convenient reference point, such as a stick laid on the ground, across the hole
- Attach a 6 inches square board on the bottom of a stick at least 6 feet long.
- At the outlet end of your tank’s first compartment, carefully push the stick through the scum layer to find the bottom of the baffle or tee.
- Mark your stick at the reference point to indicate the bottom of the scum layer.
- Raise the stick until you feel or see the stick contact the bottom of the scum layer.
- Mark your stick again at the reference point to indicate the bottom of the sludge.
- If the two pencil marks are 3 inches or less apart the tank needs to be pumped out. If the top of the scum is within one inch of the top of the outlet baffle the tank needs to be pumped.
- Lay the stick aside for later comparison with the sludge level stick.
Measuring the Sludge Level
This procedure is for determining the distance from the bottom of the outlet baffle or tee to the top of the sludge layer.
- Wrap 3 feet of a white rag or old toweling around the bottom of a stick at least 6 feet long and fasten it with tape or string.
- Carefully lower the stick to the bottom of the first compartment. To avoid pushing it through the scum layer, lower the stick behind the outlet baffle or through the outlet tee.
- Hold the stick in the tank for a few minutes to allow sludge particles to adhere to the towel. Mark the stick at the reference point to indicate the bottom of the tank.
- Remove the stick carefully and note a distinct dark stain on the towel representing the sludge layer.
- Lay the stick beside the scum stick. Line up the top pencil marks.
- Measure the distance from the bottom of the scum stick to the top of the dark stain on the sludge stick.
- If the distance is 12 inches or less, your tank needs to be pumped.
Or for those who would rather not deal with the sludge and slime protocol; call the pros at Bishop (509) 773-4707 and we’ll handle it for you!