[Rockporter]

Miracle grow is instant soluble ferts and you don't want that in a SWC. You can use 10-10-10, you can get from Lowe's and two cups poured around the edge of the bucket. You don't want to get the ferts wet by pouring water directly on it, only allow it to dissolve by the wicking action of the water. It looks like you are indoor gardening so I don't think a plastic mulch cover would be necessary except that you don't want the mix to dry out from the air.

Also, did you add dolomite lime to the mix before you planted out? Peat is acidic and the dolomite lime helps to lower the ph, I am not sure if the coir acts the same way as peat does. Peat is a much better wicking agent for self watering containers, feedback has shown because the coir can get boggy and less air travels through it.

Yes, you should have firmly(not too firm) packed the mix for the wicking action but if you packed the wicking basket enough to get the action going it should take up water just fine. One question I have is how big(deep) is your wicking basket? Is there a possibility that it doesn't sit down far enough into the water of the bucket?

I used SOBE bottles for my wicking baskets in my five gallon SWC because it was long enough to extend into the water. I drilled holes all around the bottle so the water would get in from all heights. I looks like you are on the right track, good luck.