I started a aeroponics system about a week or so ago also with strawberrys. 6 of witch are runner clones and one full sized plant I cleaned the roots really good. If you find any info on strawberry let me know to. What have you been keeping your ppm and ph at? Mines at 1150 and 6 ppm is too high for runners, they received some nasty leaf burn but are doing fine.

if accurate, 1150 is a really high ppm.

They seem to love it, I burned a few new leaf sets when it went over 1000 ppm. Sense then all the new leaf sets are growing very well, even have 2 sets of blooms coming out now. I'm getting about half-inch of root growth a day and a new leaf set about every four to five days.

I have read a lot about growing strawberry (not to mention grown them in hydro as well as soil), and the subject of increasing crown diameter was never mentioned, or even eluded to in what I have read. But if the goal is to increase the crown diameter, I would suggest to optimism the growing conditions for growing more foliage. The more leaves a strawberry plant has, the crown is bound to be larger. Then if you want to grow berry's, change the growing conditions for flower/fruit production and trim off some of the foliage to make more space for them, as well as help provide better air circulation (unless you have them spaced far enough apart)..