Chlorine and caustic (high pH) will remove organics (bacteria). Scaling is caused by salts that crystalize, and are removed by acids (low pH). Weak acids like citric or acetic (vinegar) will remove salts. Take the solids you get and put them in a glass with some vinegar. If they dissolve you have scaling if you don't it is probably biological fouling that chlorine and caustic, sodium hydroxide (lye) would remove.
Hope this helps