Whoops. This time with the attachment
I've never noticed the tangling becoming an issue unless of course I want to separate them into different containers in which case I do my best to pull em apart or I just cut em with scissors. The growth is so fast in DWC you don't even have to worry about damaging a small portion of the root system but avoid if if you can.
Also, anytime you lose you a portion of you root to mass to whatever reason always be sure to to give them a little less light. If you lose 10% of your root mass, give them 10% less light by dimming the bulbs if you got digi balasts or raising the lights a few inches.