Yeah, just fill the res back up and give her some time. Like some one else mentioned, if the leaves aren't necrotic, then more than likely she will bounce back. You have to remember, marijuana is a VERY hardy plant. It WANTS to live and will fight like hell to do so.. I'm betting your plants make it through... Hope this doesn't happen to you again though. It's always a shitty feeling to see something like that when you walk in to your grow room... It makes your stomach drop and is a total bummer. good luck to you!!!