Liquid I had the same problem with my well water and you can't stay ahead of it--don't know but there are alkalines etc that will keep your ph from staying stable. RO water solved my problem and believe me I tried EVERYTHING before I started using it. Distilled water will work too and I know there are others out there with other suggestions for pure water. You can keep fighting it but I think you're going to have to go that route. Solved my problem 100% and not only do my plants love it my tropical fish do too. Also I would wonder if your light is a little too close for that young age--I'd have it more like two feet for awhile.