Aero garden

Hi,

First and foremost thank you for providing helpful and informative information on hydroponics and it's counterparts!  I have been wanting to get into this for a couple years now, but have lacked the insight or know how.  This website and information that was provided have helped turn that spark into a flame.  

I successfully built my own cfl grow light and an aero garden using your copyright!  Although I do have to admit my aerogarden is not nearly as professional looking as yours, I know how to fix it for the next time.  Question about the water in the aerogarden.  

How often should I change it out (if at all)?  How often do I need to feed it maxi grow?

Thanks again for all the info which you have already provided.