Usually our septic tank needs emptying every 2 – 3 years. However, I had not arranged this and 5 years had passed. Recently, a dreaded ‘back up’ had reached the drain and found that the cause was a blockage in the relatively small-bore pipe between the house and the tank. On opening the tank for a surely much needed emptying we found that it was far from full. The reason is that two years ago I started using Muck Munchers which have clearly done what you say they do. Thank You, Muck Munchers. I know that our tank should have been full to overflowing (it has been before now), but this time it barely needed emptying.