Are you buying the distilled water from in the store or are you buying the RO water from the machine outside the store? Those machines are junk and they have huge ph fluctuations. I dont like grow plugs, FFOF, or heat mats. If your germin indoors with a T-5 at 3 inches then you have plenty of warmth, other than a couple drops of water every day you shouldnt be watering much at all. When I do soil grows I buy Dr earth potting mix, mix in about 30% perlite, fill up a styrofoam cup with holes in the bottom, cover it with a ziplock and set it on my water heater for 2 days. They always pop. Take the ziplock off and put them under a 23 watt cfl for a week. Repot into a 6" pot and put them under you T-5 and let em fly. Iv never burned a plant with that potting mix, ph is great, give her some organic veg ferts, molasses occasionally , let her dry out in between waterings and your good for veg