The day you decide to give only pure water, go ahead and flush the plant out. Use 5 gallons of clean water for every gallon of soil. So if you have a 3 gallon pot, dump 15 gallons of water through it. I suggest putting a wire mesh over your bath tub drain, and doing it in there. You want all 15 gallons to run through the soil and out the bottom of the plant to "flush" out all the built up salts and nutes. laterz..