Hmm, Terri I think if the soil alkalinity was the problem you'd be seeing more chlorosis on the leaves - yellow leaves with dark green veins.
Are the plants getting sunshine all day? What puts sugar into the berries is the healthy green leaves making lots of sugar from photosynthesis - converting the sun's energy. If they aren't getting enough sun they won't be sweet and flavorful. Can you cut back some overhanging branches around the strawberry patch? At least 6 hours of good sunlight is needed for sweet fruit.
So, by all means fertilize those plants (the acid fert will be fine) so that they will grow as many lush green leaves as possible before the next round of berries. I hope you planted an everbearing not June-bearing variety? If not, you'll have to wait until next year to continue your experimenting.
The other thing to try is to leave some a day or two longer on the plants to see if they sweeten up. Try one or two that are a darker red color. A berry won't become sweeter after it's picked, no matter how long you leave it on the windowsill. They need the leaves to make sugar for them.
