I have an old septic system (1980) it is saturated. Supposedly needs to be replaced. They want to install a Jet aerobic system-($7100 to $8500) due to rock--an aerostream system is much less($1000?). Which would best in your opinion?Supposdedly aerostream will clean out the old system and get it working and avoid replacement. I do not know anything about those two systems and I do not know of anyone who has used them. Any info. is greatly appreciated. Thank you.