root rot in soil? ...hmmm. not saying it's not possible, but i thought the "rot" was attributed to non-beneficial bacteria and fungus. i would think, for the most part, micro-orgs and the soil itself would help to protect against it. i would be more worried about root binding in soil.
...if you're watering too much, i could see root rot might happen. to fix, transplant into new/bigger container 2x bigger than current container. use 1:1 ratio of perlite and the soil of your choice. pack lightly then transplant from old to new container.
cut back your watering, if indoors to where you can stick your hole finger down in the soil and feel mostly dryness. the tip of your finger should feel damp, not wet or moist...this signifies when the plant is ready for some more water. outdoors, go 1/2finger to full finger <<<does that sound dirty?
hope this helps. post some pics, that may be able to help us more.
o2 to the roots is the best way to combat root rot.