What a great week! The plants are doing much better with a flood and drain system. I flood two hours after the lights come on and again 6 hours later, (no flooding at night). I also changed the strength of my nutrients to match a flood and drain table on the GH website. I have a reservoir under the table that holds 10 gallons of nutrients. The pump circulates the nutrients thru a chiller 24/7, which keeps it at a perfect 18.5 Celsius. When I need to flood the tray, I place the hose in and let it fill to where I want it. The return hose has a plug, which I remove in an hour or so, to let the nutrients back to the reservoir. The plants seem to like the rhythm of the nutrients flooding in and out, it could be just me.