If I were your mother, I would have turned it around and asked him "Well Mr. Septic Sucker, since you think Rid-Ex is not good for the tank, what would your recommend we use?" I am sure he would try to sell you some overpriced liquid that you could probably pick up at the neighborhood hardward store. Maybe he just has a thing for your mom and wants to come back more often to visit her and get paid for work?

Will a septic tank cleaner harm my system? The biological additives are unlikely to be harmful. The chemical additives could definitely harm your system. These products have the potential to sterilize your system temporarily. The resulting passage of raw sewage into the drainfield will hasten its failure. The acid and alkali products can corrode the plumbing and the tank. The organic solvents pass through the system unchanged. They can then infiltrate into the groundwater, creating a chemical plume that endangers nearby wells. Most states allow the use of biological additives, realizing they are, for the most part, NOT harmful to the system, but also realizing that there is little evidence showing them to be beneficial. (From http://www.laundry-alternative.com/septic_tank_cleaner.htm)

Speaking from the perspective of professional in the field... I have worked as a septic pumper/installer for over 35 years. In my experience, I have ran across this question hundreds of times. Upon excavation of failed septic systems, we always obtain a background of past use and/or neglect. Rid-Ex has been one of the main culprits of numerous failed systems. I've said this before and I'll say it again: It's all a scam! There are many products purported to make a septic system work better. None are proven good, and many are proven bad. Why take a chance on any of it? The septic tank was invented in the 1860's and little has needed to be changed since. It has been discovered through the years that regular maintenance is the key to prolonging the life of a system. Just pump the tank out every 3 to 5 years. I pump tanks every day for $160, if you skip a few pumpings for a few years, you save a few hundred dollars. After Rid-Ex has collected their money from you and you still end up with a dark stinky wet spot in your lawn, you can still call me. I install septic systems from $3,500 to $18,000. You just can't undo that kind of damage (to your system, or your wallet). So, you can pay me now, or you can pay me later.

It isn't harmful but it does nothing. What really works is not putting junk down into your septic system. Don't pour grease and oil down your sink. I've seen people pour bacon grease down their drains and then wonder why they have problems with their septic. Keeping food and especially any type of fat from killing off the good flora living in your tank is one of the best things you can do. Other things to think about is being careful what toilet cleaners or any kind of harsh cleaners you use and send down the drain. Think of your septic tank as a compost pile that you would use on your veggie garden. And then get it pumped every few years. We had our tank staying very happy for 30 years with only 2 pumpings because we kept it happy and healthy.

It's not good for the septic system but with creamer in your coffee each morning will cut down on flatulance

I use I lb dry active yeast. If you pump your washing machine water into your septic you kill most bacterie, it's something my dad did, I also pump it every two years.