When should I throw out clones???

Had problems with an aeroponic cloner, that the PH kept going high, from high temperature of solution. The first to die off had liquified stems, below the neoprene inserts. Have many that the stems are brown below the insert, and the brown rubs off at slightest touch. It most be the outer layers dying.

Should I just chuck any with brown. The only ones with healthy roots, are all green.

Thanks for any help!!!!

Just checked them all. If it is brown, throw it out, or cut off the brown, and lower stem in insert, if the top looks great. Some inserts had amazing root growth, with brown rotting stem below. The healthy looking ones, I salvaged, so far.

always cull the weak growers. the disease spreads if u dont. expect attrition till u got the technique dialed in like after 6 or 8 rounds