It sounds like these new swc's have you stressed as much as the plants in them. Well, it's nothing to worry about - you've just been given a lot of different variables to sort out. This swc stuff is easy..... :)

First of all, you need to stop the top watering...Your plants are showing signs of too much water. Second, the 70/20/10 mixture is not suited for growing tomatoes in. Reason being - it remains saturated all the time, especially if not covered by something to shed torrential rainfall.

Mix combinations are suited for particular plants, and although corn, broccoli, and a few others would do great in the mix recommended by the kids over at globalbuckets, tomatoes and peppers will fail everytime.

Also, you can't use the finger test to check moisture levels in a swc - as the moisture content will be higher as you move toward the bottom of the soil mass.

The other mixture you're using should work pretty well in my opinion, and I feel that your top-watering out of concern is actually creating the plant problems you're seeing.

EG

Here is a link that might be useful: I share my thoughts, concepts, and ideas about swc's here...

I do have the buckets covered with black plastic. The leaves on some of these plants were already yellowed/spotted (just the bottom sets though) when I bought them from the garden center.
So since I've done a few of these buckets with the soil mixture recommended by GlobalBuckets, what should I do? Our those plants definitely going to die? Should I dump them, and redo the soil mixture using the 3, 2, 1 mulch/miracle grow/perlite combo? Thanks.

Well, i'd either dump the mix and increase the drainage characteristics drastically by incorporating lots more perlite or bark pieces into it, or simply limit the wicking of water by purposely only adding water to the reservoir when the plan needed some. (Basically turning it into a bottom watered container)

EG

I don't know about the first
mix but the second mix is way
too wet,try 60% peat moss and
40% large perlite,god luck.

les :)