Newly purchased tubes output is much stronger then older tubes. Three inches from the tube is too close especially for new tubes. Your plants are actually burning from the light and heat. Same thing happens if you place them out in full sun without shade.

I would back the lights off to between 8 and 12 inches from the plants after removing them from the light completely for a while so they can recover.

Julie64, I agree with wec1957. I have written several tips about streps on the forum. If you go to page 2 Re: Streptocarpus, I explain how I grow my streps under T-8's. 3", especially with new bulbs is way too close for plants. That distance would be good for starting seeds but even then I would back off another couple inches.

davioletman