You can also mix nutes, 7-3-6 is a little low in Phosphorous for flowering, too much N not enough P. Remember it's the ratio's that are important, you can increase concentration by decreasing your dilution ratio. Too much N and not enough P will cause the plant to get kinda leafy. Why not mix up some half half solution of the 0-13-14 and 7-3-6 at the beginning of flowering and then after 2 weeks maybe go 1/4 7-3-6 and 3/4 0-13-14. Maybe at week 5 or 6 (for 8 week strain) go to the 0-13-14 for 1 or 2 weeks, then just water till done.