Bill; No I don't grow flood and drain I top feed only. Grow rocks don't hold much water and the roots need air and room to breath so I like to use top feed drip lines. I do regulate the water cycle though. I like to run full on drip when the lights are on and 15 on 30 off in the dark works just fine. The last 3 weeks of flowering I do bump it up to a full 24 on. Lights on or not they can use the extra nutrients when they are growing at their most important point in their cycle.

Now let me clear something up when I say drippers I mean it's just 1/4" tube drilled into 1/2" PVC manifold by a 10-32-thread fitting. 2-90 deg risers make up the feed line. I don't use emitters or anything to hold back the flow or regulate the feed. They just get clogged and are not needed if you set up your system right in the first place.

You can see from the picture how I make my feed lines. You can swing them away to remove the net pot. You can even rotate the plant to improve the light to other areas of the plant with out moving the feed line too.

Does that answer you question?