Aeroponics help needed

Hey everybody! I'm brand new to the boards and have some questions about aerponic growing. First off, I built my own grow box (I'm handy like that) and it works well. I have the pump set to mist every 15 minutes for 5 minutes. I also am using a 1000w HPS. Heres my questions: When you mix your nutrients is store bought water acceptable to use(water in my area is rough)Also how often do you change it out? Is there a universal nutrient I can use, or is there different nutrients i have to use at different stages of growing? And this whole Ph thing. How often do you check it and what do you use to bring it either up or down? And the last Q: When you grow with this method how do you keep the seeds and the roots fed when the roots have just sprouted and have not been exposed to the mist. And what are some other growing mediums besides rockwool that are good?(I saw a pic of this guy's set up and it looked like he was using nut shell type of things...what are those) Thanks for any help that anyone can offer!

I am not sure I can completely answer all your questions, but I will try on the ones I know. If you use store bought water I think distilled water would be even better than other water anyways. It has all the chlorine and other minerals and salts out of it so you have a clean water source with no contamination. Your pH I would check at least once a day. There are all sorts of things you can use to bring it up or down. Easiest thing to bring it down (acidic) is just something like vinegar. Baking soda is an easy way to bring the pH up (alkaline). You can also buy pH up/down solutions at some plant places and also places that have fish stuff should have for fish tanks. I am not sure about the seedlings and stuff but I think at that stage when the roots arent present as much the growing medium soaks up the nutriets for the time being (not sure though completely, guess).