I'm in the same boat. I have to add another tent myself in January but I want to start that tent with only hydro and then gradually phase out the soil grows from the big room. I've also just bought all my seeds for the next 6 months so in January I'll be planting one photo (Haze and cheese selections) a week, to keep a harvest of one photo a week, with probably 2 autos along with it for personal smoke. The whole hydro thing has me baffled though to be honest, I hear like epm or is it ecm? etc and it just doesn't mean anything to me. I grow in soil and read the plants, it's a very forgiving medium, but I'm in a built up area so it's not sustainable getting rid of 30 lts of soil in the bin. So hydro and probably LEDs for the new tent and a mix of bubble buckets and soil then till I get rid of all the soil plants? I really dunno.