Kind of annoyed, I just had to merge four threads on the same topic...

Please fill out the troubleshooting form. You may have to do it twice- once for your mother room and once for your flower room. Sickly mothers give sickly and weak clones. You should be concentrating on making your mother room conditions perfect so that you have the healthiest moms possible before evaluating whether you have some irreparable genetic damage. I am running at least a half dozen clone-only strains whose genetic age is 10+ years with no loss in vigor. Of these, two are over 20 years from seed. Weakening over time IS possible but not the first thing that I would assume given the description- instead, look for rootbound mothers in used-up crappy soil, giving pathetic slow-rooting and hard to harden-off clones. Regenerate your mothers in the best quality soil you can find. I have recently switched to BioCanna medium cut with vermiculite for my mothers. It is very stable over time. Also try running a silicate supplement in your mother room to strengthen leaf tissues. This may be applied as liquid fertilizer or as a foliar feed given once a week as directed on the bottle.