Only fairly clear water should exist between the scum and sludge layers. This water fills the second chamber of the tank where it becomes even more clear. Solid material overflowing into the soild absorption area should be avoided at all costs. It is this solids overflow which clogs soil pores and causes septic systems to fail. Bacteria must be present in the septic tank to digest the organic solids.
Bacteria are very sensitive to environmental changes.
Many home-care products used in most homes every day will destroy bacteria. Home Reference Book by Carson Dunlop 1999-2000. Optimized for Netscape 4, Explorer 4 or better at 800x600 resolution.