I just tried the blue and red cloning light for the first time , clones went well, took straight away no droop or yellowing but after 5 weeks the clones although looking very healthy , had gown heaps of roots and stems had thickened, there was no real growth on top , I put a couple t5 over them and a week latter they have gone crazy , this is a good thing for me as I perpetual grow and it has always been a struggle keeping clones small until Im ready to put in , I would normally be cutting the tops off at 5 weeks because they are to big for my cloning tent ,this light could be the answer , first time though will see what happens next time around