Posted 3/8/2019 07:24 (#7366786 - in reply to #7364057) Subject: RE: Kitchen sink drain
I imagine it just modifies the pH a little bit.
The small amount of acid or base you add (that’s all drain cleaner is, but there are both kinds so don’t mix them unless you want fizzy droplets spattering all around) changes the pH some in the septic tank, time it gets down there. I imagine it remains pretty concentrated in the pipe and, once it clears and goes down to the tank, is pretty dilute. And of course you are continually adding more water to further dilute the stuff.
If you are worried about it, just turn on the shower for an hour while the drain is getting unplugged, that’s an easy thing you can do to add water to further dilute the product in that tank, and prevent the microbes from getting shocked.