Yellowing Fans....Toxic Salt?
KB has been given several chances to grow the fuck up and blew every one of them. He's out of freebies and won't be back.
Flsuh differs from over watering in that over watering happens when the soil does not have a chance to get fairly dry a couple times a week. You should give a nice weak watering of your fert at 1/2 what the bottle says, then let the plants do their thing, use up the water in the soil, get on the dry side (stop short of wilt), and then resume your normal feeding.
I wouldn't use runoff on boxwoods since in my experience they can be twitchy and scorch easily. Plus you don't know quite what the chemical profile of the liquid is, and chances are that it's got salts in it that aren't all that great for most plants. So I'd say just toss it. I know... re-use when possible... this isn't one of those times though.
I didn't see the bubbler thread. I'll go poke around.
take care,
pats fan. :D