Starting Seeds For First time Aero Grow.

Whats your guys favorite/most effective way of starting seeds for your grow. I've been told by friends of mine not to use Rockwool to start your seeds because they can change the PH of your water easily, I have a Seed Starter --> http://www.htgsupply.com/Product-HTGSupply-Seed-Starter-Kit but i used it once and when the plants got about a ich or two tall with a inch tap root the started to die and i ended up completely losing all of them so i would like to use a different method which has worked for other people. All information is greatly appreciated. This is my set-up Btw, It's an aeroponic set-up with a 600w HPS dimmable light. How tall do my plants need to be before i put them into this set-up. Thanks everyone!