My system has two tanks 1000gal. The problem I am having is in the first tank from the house. The paper builds up at the end of the pipe. Every so often I need to open the top and move the paper or water will back up into the house. My system is 13 years old. I have it pumped every other year. There is only my wife and I living here. Every time I have it pumped out I ask the person what may be the problem. I never get an answer.