Distilled water will actually draw nutrients from the soil. As the water molecule has altered during the distilling process. Did you know drinking distilled water for long periods of time will actually cause health problems? All distilled water has is a lower pH than tapwater..aside from that it actually lacks things the plant needs. As for RO water.. it's in the same category really... designed for drinking not growing.. but some have adopted this idea that hyperfiltered water is better for your plant.
24/0 is also only really suggested for the first 2 weeks of the seedling's life.. 18/6 is a much more reliable and comfortable light regimen for the plant. Plants need time to rest too. Just as everything on this earth does. 24/0 is un natural.. and the plant knows it.