First thing, give them water or nutient, by hand if power is down. Then see how they react.
Plants are very resistant, some might pick up.
There is always time to trim later if necessary.
Good luck. Chefmichel.

I would give them a couple of days. If the tops continue to be shrivelled,, then trim them back as Michel says, to just above the next healthy leaf node. You will soon get a new sucker growing there which can serve as your main growing point.

I like using a more forgiving media like perlite or pine fines in at least a 5 gallon container which will give you atn least a 24 hour window in case of a power outage or pump failure.

Thank you for your replies. It would seem you are right> Already there is evidence that new growth will shoot. What a day yesterday I had. A $300 speeding fine really topped it off doing 60 in a 40 zone. . May I ask... when I first set my rain gutter channels up I mixed the expanded clay rock with coconut fiber. The purpose was to do exactly as you suggest to give a more forgiving medium. What happened when I first tested that system out, even though I has used a pre filter of insect screen before a stainless steel fine mesh is that the fibre collected around the filter and prevented the water from exiting. I considered just slowing the flow down to just a slow drip but the whole system is pretty big. Using hydroponics both inside the glass house and in the garden too would mean the pump would operate for a lengthy time.> you comments welcome.
seonau

I like a continuous drip 24-7; tomatoes and other vegetables like it just fine and it is less wear and tear on the pump. If you get a Maxi Jet pump they draw very little electricity.

(If you are using gutters for tomatoes you should re-think it). Tomato roots are quite large and will pug up gutters, drains, etc and will disrupt flow to plants further down the channel. Bato buckets are better. You can get them from Crop King or make your own. There are plans available on the web at various hydro sites.

Seonau, I had similar problems in which I used the Perlite & peat media (in separate systems). Both came through the filter, & because my system was recirculating went through the pump. When I used a smaller filter the system plugged up. I finally decided to go to a NFT system. Have you ever thought of hybridizing your system? I am going to try a wick/NFT hybrid system. One problem is the wick will need to be intermittently changed due to algae.

Another possibility is devising some sort of system in which the plants are sprayed by water pressure.

Thank you all for your most welcome comments.
My system has become too large to change right now, with flowers growing around the outside of my G> H> and with the veggies within mostly doing fine. But I take your hints on the gutter system and maybe changing it,as being good ones. I have not joined the whole lot together in one large trickle type flow but instead broken the channels up into individual mini systems where the plant types are all together only. I have one pump operating all of this but have two more new spares ready just in case.
Hey by the way looks like the toms will be ok.
I am very new at this and have yet to taste any home grown fruits at all. Feel free to contact me with your ideas, I would especially like to see pictures of what you have set up and help and suggestions on how I might modify my existing system.
seonau