Ask the manufacturer if they can be used in both hydro and soil. If they sell a line for hydro and soil, I would ask them what the difference is. Your going need Hydro Guard or something with Bacillus bacteria to keep from getting root rot and more Cal/Mag than you would use in soil, water has none. 

I would start out at 1/4 to 1/2 strength, most nute manufactures want you to use too much of their product and it will stunt growth by locking out intake. But unlike soil grows, the mistake you make today will be visable tomorrow or sooner and the recovery takes about 2 days except when you forget to turn on the air pump for 2 days.