my lateral lines are starting to show signs of black water. my septic tank has never been pumped in 30 years, until i saw this in my laterals. the man who installed the septic and laterals years ago said as long as i used ridex regularly, i would never have to have the tank pumped. we were not regular, so now we are starting to pay the price. i was told by the man who pumped the tank recently, that bakers yeast is just as good as ridex to build extra bacteria. i was also told by someone else, that all bakers yeast does is cause foaming.
should i continue to use ridex once a month in order to try and clear the laterals from any blockage.
we dont put grease in the lines, nor drive over the lines, nor roots from trees, etc. we do however run showers, and laundry freqently.
i was thinking of putting a double portion of ridex in, and then running the shower to force water to take the ridex out to the laterals directly instead of letting it sit in the tank. thus hoping to put the ridex bacteria at the areas showing some blackwater.
any help you can give would be appreciated.

what do you think. what is my best option without