FWIW, check out industrial "cleaners" with vacuum trucks. I had a company for a few years that had a huge truck with what must of been a 10 or 12 inch diameter hose. The attendant told me they could suck bricks through the thing. They had my pits done in 1/4 the time of normal septic services.
They finally gave up doing the "little guys", and I couldn't get them to come back.
It was much, much cheaper....because here in the NorthEast, they charge for BOTH time and amount hauled away. A 3/2 costs me about $1800....and I can get by doing it every other year.