Hi Lura –
If your hydroponic tower garden is only receiving moderate sunlight, I would recommend moving to a higher light area. Plants such as tomatoes and peppers need at least 8 hours of direct sunlight everyday. This time can be split, but it must add up to 8 total hours. As for the pollination problem, plants in the squash family will often will open male and female flowers at different times. Having multiple plants of one species helps to combat this issue. It is also necessary to make sure pollen is traveling from male to female flowers. Male flowers will have one big anther in the flower resembling a q-tip or Popsicle. Female flowers have stigma which form a swollen cluster atop a ‘pedestal’ called a style in the center of the flower petals. An electric toothbrushes with a cotton swab stuck to the end will help mimic the movement of bees. Use the toothbrush to gently shake pollen from the male flower. Once the cotton swab is saturated with pollen, turn the toothbrush off and place into the female flower. Turn the toothbrush back on and gentile add pollen to the female stigma in the center of the flower. You can also remove the male anther from the flower and apply it directly to the female flower. Both of these methods will produce fruit if executed correctly.
As for a nutrient line, I’d highly recommend the Floraseries Performance Pack. These nutrients will take your plant from seedling to fruit, simply follow the hydroponic schedule listed here. Less is often more with hydroponic nutrients, be careful as to not burn your plants. Start with a very small amount and work up from there.
Happy Gardening!