so to basically get all the positive stuff above in one list, keep coco wet, get a little bit of runoff each watering, about 10% is sufficient, if you get it every day, if you only water every other day (which isn't recommended) get at least 20% runoff.
if you're growing in cloth pots, elevate them so they aren't sitting in the run off, the reason you want the run off is to get rid of the depleted salts the fertilizer you fed them were bound to, if they're sitting in it, they just reabsorb it and cook your roots.
don't worry so much about run off ph, just check your meter now and then, make sure its accurate. feed at the proper ph (between 5.9 and 6.2) and the root zone will take care of itself.
oh, and the upper pic look like the early stages of magnesium deficiency, the lower one looks a little like the damage that you get when you have damaged roots...