I always hand water seedlings in DWC before even introducing them to the system. Just drain to waste in an empty bucket.
Like
@rkymtnman mentioned you want them too seek out water. Overwatering is very common in DWC with people starting seeds directly in the system. Running to high water levels saturating the medium.
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This is the same day before I introduced them to the system running water and aeration in the buckets. Just hand watering up until this point. Cheers!