DeltaEyecommentedweek 313 days ago
@gottagrowsometime, Okay, I'm guessing you checked the pH of the water after you had soaked the rockwool cubes in or the runoff from the cubes. pH 4.5 just sounds really acidic to me to start with, maybe if your rockwool is really alkaline (like 9 sounds like...) and you were soaking it in a small volume of water.. I just measured the pH of 20L of water that I had adjusted to around pH 6 before adding twenty Grodan 7,5cm x 7,5cm cubes (1 liter of pH 6 water per cube) in and been letting them soak for a week. The pH had only risen to 6.7-6.8.
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