I really doubt if it was the roots touching drainage rocks. They grow well wrapped around nearly anything buried in the ground so it must be something else. If your leaves are spotting then dying off it's most likely your tap water that needs fixing. And using drainage rocks aren't necessary if using pots with drain holes in them and will only mess up the weight when checking for watering needs. Next time...

Sorry, but I wasn't using tap water. Nor did I have spots; the malady in question was severe yellowing, following by fan leaf die-off. The containers did have drainage holes in them as well btw... A layer of stones was used as I didn't want the drilled holes to become blocked with compressed peat or chunks -o- perlite. Worked pretty good I thought, as my run-off was pretty free of medium matter.

So, next time? Hydro? Coco stuff looks interesting...