well im no hydro guy but im pretty sure you dont use soil in hydro you use medium, is that what you mean?
Look for or ask at a indoor garden store for Hydroton. They are expaned round clay pellets you use for your medium. I think you might have to rinse them to remove processing dust and you might have to adjust them for a balanced PH with a hydro medium buffer. I know you have to do this with rockwool cubes. Also the containers them selves are full of drainage slits like a plastic container strawberries at the supermarket are packed in. I do believe Home Depot has them cheap for small fountains and pond gardens. Peace, GB