Questions on first part of next grow

Hi right now my seeds have sprouted and are only like 4-5 days old. This is my second grow, first one was sucessful just using only floros and miracle gro. This time around I`m using Advanced Nutrients beginner 3 part and a 400watt mh/hps light. I hooked everything up and have a few questions.

First off, I wanted to know how far away you should hang your lights from. I heard everything from 24" from top of plant to 6-8".

Second question is about the nutrients, I plan on waiting probaly 20 some days, till they start showing signs. I`m wondering how exactly do I do this? Do I start out with just the Grow and micro, When I start flowering add bloom and bigbud. Then after a week or two of flowering Do just the bloom and big bud?

And finally PH..... First time ever trying this since highschool. I`m using ph drops to test. Right now I only have Pool phdown and aquarium phup. I pretty much just went with eye, added the phdown, it went to 4 and down. I then added some phup and actually hit the nuetral, around 6. There's gotta be an easier way to ph, I figure it's kind of an aquired skill.

Allright thanks for any info.

Lessee,

Sounds like you're talking hydroponics, right? I'm gonna assume you are, so if not speak up.

Lights - you hear different distances because people have different temps. The hotter the lights, the farther they have to be. If you've got a good air cooler you can move them a lot closer. Use a thermometer and get the lights as close as you can without cooking your plants. Make sure you give it 15-20 minutes in each position to stabilize the temps. (Easy way to test is to hang the thermometer from the light with some string or something and move it up or down until you find the sweet spot.)

Then move the lights as close as you can, leaving a few inches of growing room, and keep a close eye out for light burn. Make sure you keep moving the lights up as the plants grow.

Nutes - Most people say to wait 2 weeks before adding nutes, and then add them at 1/4th strength. That's what I do too, though with AN it doesn't hurt to go a little weaker. Their stuff is pretty concentrated. Bring the concentrations up gradually and watch for nute burn. Bigger plants will usually do better on higher ppms, the little guys will burn fast on even low ppms (which is why you wait awhile before you add any.)

pH - You want to avoid yo-yo-ing your pH as much as possible. Always try to add too little up or down. It's easier to add a little more than to correct too much. pH up and pH down don't really play nice together. (Never add them right to each other) In a good amount of water it's not going to explode or anything nutty like that, but it ups your ppm enough to possibly cause problems.

Personally, if I over-correct the pH I just throw out that batch of nutrients rather than risk putting too much up/down in the water. Strictly speaking that stuff isn't good for plants.