just wanted to throw in, that your plants take in different elements from your nutrient solution at different times. by changing out your solution regularly, you are making sure there is a enough of whatever they want, whenever they want.
greenthing- i like to run a small fountain pump with fountain attachments inside my reservoirs along with 2 airstones. the pump shoots nutrients against the lid and it splashes all over the roots.:thumbsup: just my thoughts on the subject.:S5:

PS- welcome back cannacom and all us members!!