Grease and residue build-up in drain

Good morning,

First off great website, lots of useful info.

A couple of years ago the drain from my kitchen sink was slow/clogged. After trying different hardware store products (ex. draino) the problem was still very much there.

So here's my set-up... our house is rougly 30 ft wide and of course the kitchen drain and the main drain stack are at opposite ends. Which makes for a long run with poor slope. To find the prob I ended up cutting my line around half way. I used a plumbing auger to find the prob and located it 3/4 of the way to the stack. Blocked almost solid with grease/residue. Flushed that section of the line using a garden hose connected to the hot water tank... worked really well.

So now in order to prevent the same problem what should I do or use. Trying to flush the line with hot water doesn't really work due to the length of the run and slope... the water cools too much. Alot of products are effective at the source of the prob and not down the line.

So what advice would you have to clean and maintain the drain line to prevent this prob? Keep in mind that we are on a septic system so I do not want to harm my system with harsh chemicals.

Thank you very much

Sylvain