Hydro plants-droopy leaves and red lines on stems

I have 2 low riders in a 14 gallon resevoire. The larger of the two has droopy leaves and red lines up stems; almost like veins. They are a few weeks into flowering and the leaves look fine.

They had a root rot problem but I cleaned everything very thoroughly and added hydrogen peroxide to the solution. The plants were doing great for maybe 2 days but now the one is droopy. PH is fine, they have adequate light. I have 2 6 inch airstones, one for each plant. Any ideas?

DID you just transplant them?

no they have been in the system for a month and a half. did some trimming a few days ago but they had already recovered from that.

Did they dry out for a short period of time? What did you do different if anything.

The red lines on the stems is perfectly normal.

they're probably over watered.... any pics...