2 tanks = $400 here. If you think BC is ****, try Kalifornia... but we won't go there. Reminds me of a joke I can't post.
Our system was a cheapie redneck diy project that came with the house. They used the white flexible 4" drain pipe for the run from the house down to the tanks. Earth pressure forces that into an oval, allowing enough liquid out to attract roots. Roots close the run down to about a 1" opening or less, and then, sludge happens... the early warning system is a pool around the base of the master toilet. I installed a clean out and got a 50' tape snake (the kind that rolls up like a flat spring, and occasionally explodes out of the metal frame). It has saved me hundred$$ in roto-rooter calls, but not my idea of a good time.
He quoted me $1200 to replace the 60 foot run with "real" pipe and fix the T inside the box that was likely blasted out by a roto-rooter. I consider this well worth it and this thread reminded me to call him again... he was too busy pumping with our latest artificial housing boom back in May to tackle a rebuild.