Pick the strongest one and grow that. It’s better to grow one plant well then 3 plants badly. As it’s your first hydro/dwc grow, you’ll learn how ph is directly effected by nutrient levels AND by the plant/bacteria adjusting the ph for optimum nutrient uptake. There’s a lot to learn the first time with dwc. Keep it simple and throw all you attention at just one plant. Trust me, when your sitting on an upturned bucket, lookin at ur plant, trying to figure out what’s wrong, you only want one plant to worry about. Patience, Grasshopper. K.I.S.S.

P.s. Get a proper PH meter and calibration solution/powder. I prefer the powder sachets as it doesn’t go off and it’s easy to deal with. Accurately knowing the ph in dwc is important.