I went with clones, so I used 1/2 strength DynaGro Grow from the start. With seeds, I would just use pH’ed water until the first pair of leaves showed up. But I would probably plant seeds in rooting cubes, and plant them in beer cups of coco when some roots showed on the edges of the cubes.
Yes, water every day with nutrient solution. Never use water alone until flush time at the end. If you use just water in coco, it washes all the nutes out, unlike soil. Always mix up nutes and THEN adjust pH. Flush at the end with pH’ed water, just so you don’t shock the plant.
I use tap water that has plenty of calcium and magnesium in it already to thoroughly wash and break up the compressed coco cubes. Takes care of any salt, too. Once the coco is all broken into individual strands, pour in cloth pots until you have enough to fill the pot. Then wash with a few more times that pot volume of water. of water. Let it drain: Ready to use.