The pH dropped three times in a row below 4.0 over night. The left plant has a lot of issues with that and is stunned. Right is doing ok and was overtaking left in growth but not in bud size. The red coloring could appear because i didn't use any pH-down (H3PO4) the last week and always corrected the drop with a few liters of non pH-regulated fresh solution or only tab water. So it could be a lack of phosphorus. Today (d64) i changed the whole reservoir.
i know its 3 years ago but how did you like the migro light? i just bought the ARAY 4 for a 120cm x 60cm tent and would like some input or maxbe a tip (: