Looks like you just had some early problems with ph being too low, causing nute lock and burn. The ph being off by a factor of 1.0 might not seem like a significant factor, but it is. Ph 5.0 is 10 times more acidic than 6.0...so a seemingly small amount can make a big difference, especially in cases of nute lock and other microbiological processes.
A while back, I didn't have a ph tester handy and did some guessing with my water before tossing it into a bubbleponics setup. Things seemed fine for a week or two, and then I had the same drooping patterns your plants show. I quickly picked up a new tester and my ph was sitting at around 7.5 at the time. I quickly adjusted the water and within a few days things were not only recovering but started taking off like they were making up for lost time.
Keep in mind...when you get some of that damage you don't always see those leaves that show(ed) the damage to recover fully...the rest of the plant may grow fine after it recovers, but those leaves could stay...scarred, for lack of a better term.
Now that your plants are growing again and apparently not drooping so badly, I would simply watch to make sure those older leaves get no WORSE. Other than that, focus on any possible damage appearing on new growth.
Make sure you can test your ph without too much trouble and keep an eye on it.
Try not to over-fertilize.
Aside from that I can't think of anything else right now.