Through assisting customers with an occasional unique situation, experience has taught us that other factors that could be impeding treatment: -       Bacteria are dying:Use of root killer, antifreeze, homemade treatments or combinations of treatments (that cannot be guaranteed by DOWN JOHN) could be killing off the live bacteria and interfering with the digestion process.   DOWN JOHN was designed by an Industrial Scientist so the treatment is a complete kit as is.-       Disruption to Use:If the system has not been used in over 1 month, the bacteria are starving and dying off.-       Obstruction:The presence of roots in your system could cause problems. Also, missing lateral line caps could cause dirt or sand to enter the pipes. Occasionally, collapsed pipes or quick fixes are impeding flow.