hey RZ...

FYI - what causes root rot is warm water (over 75 farenheit) and lack of oxygen to the roots.. When you start to get root rot, your roots will be very very slimy and brown and they will break easy when you touch them..

You should keep all dead matter out of your reservoir... dead matter consumes valuable O2.

You may even consider sumplementing your reservoir with Hydrogen Peroxide once every 7-14 days..

Air stones in the reservoir also help tremendously with root growth..
Especially if your roots eventually go into your reservoir..

: )
cheers