You can't really have a weaker plant since they are all the same plant to begine with. It's how each plant is treated separately that gives them different personality. Let's look at the condition of the host plant. Is it in vegitative state? Did you take a cut THREE nodes down? Are there enough leaves on the clone to give it the light energy it needs to make it's roots? Is the humidity high enough around the clones? They need a humidity dome over them and the dome itself sprayed with water. (not the clone) How much nutrients are in you water? Can you take a pic?