I use the Advanced Nutrients pH down, which is pretty strong. For my 45g / 170l res, 2-3ml will make a noticeable difference. Go slow and stir between each addition. And remember that your nutes will probably lower the pH some as well.
I use the EZ-Gro plugs, like the root riot ones. Don't worry about trimming anything off, just put the plug in a layer or two of hydroton and then fill in the sides. Good luck!
When I started out I would water my seedlings manually until roots hit the res. I've since found that they grow more lateral roots if I don't water them manually. The moisture in the bucket is enough to keep the hydroton wet, and that's plenty for the seedlings.
pH will go up when the plants are consuming more Anions and go down when they're consuming more Cations. Mine always seem to drift up in Veg and down in Flower. I just had to pull out my pH up for the first time in week# 6 of flower, they crashed all the way down to 5.4 twice!
Take the water out of the tray. Seedlings don't need nutrients for the first couple of weeks. I use rooter plugs and trays to pop seeds as well. The plugs will retain the correct amount of moisture without sitting in water. You are drowning those poor roots.
Thanks @StonedGardener , I am trying to roll with it as much as possible. Oh, I have not had a problem with bugs (yet), and I have carbon filters on the intakes on the tent, but I still have plenty of yellow stickies!
New grower here. I have ordered three different strains from ilgm and all arrived promptly. I have germinated 10 seeds with 100% success. I am still 6 weeks from harvest, but the plants are growing great and I am very happy so far.