I can't really say i'm speaking from personal experience, but i've been doing a lot of forum reading on deep water culture (dwc) and drip system setups.

IMO, i think the roots are growing because they have to space to do so. This is not a bad thing. Large roots system means the more nutrients it can absorb. Eventually the roots may reach the drained water. This is okay because you plant will take in any left over nurtients when it needs to feed. That said, i would still empty the bucket once a week so the water doesn't get stagnet (sp?).

I've heard of people trimming roots mass that were overgrown, but i think that's in extreme cases.

Hope this helps!:thumbsup::jointsmile: