Tomatoes, peppers and eggplants are all "nightshades." We aren't supposed to re-use soil for those, and absolutely not if there was any plant disease last season.

So, I think the best-practice choice wouild be new soil (and wash the containers) before planting more nightshades.

Or, you could reuse soil and plant something different and robust, like green beans.

For some reason many sites list green beans as the number one best container vegetable crop.

Growing in self watering containers is different from growing in the ground, where it's best to rotate your crops, especially the ones from the night shade family. That's largely because of soil borne diseases like verticillium and fusarium wilt build up over time.

I am new to self watering containers, but I've been frequenting the Earthbox forum and followed the activities of Raybo, who invented the Earthtainer. They recommend removing the old plants with their rootballs and about 20-30 percent of the old potting mix. Then they mix in the new mix along with a full dose of lime and fertilizers as you did the first year. You can do this for a couple of years so long as your mix doesn't get compacted and your plants stay disease free.