Just changed res water, plants drooping.

I've got a DWC system going, and I just changed out the res water for the first time about 30 mins ago. The ppm's were starting to get pretty high.

I drained all of the old res water. Then added freshly mixed solution.

All of my plants are drooping now. They are about 3 weeks old.

Is this normal after a res water change?

Looks like maybe you've used cold water or mixed the nutes too hot. Give em a few hours before you freak out.

Did you pH the water AFTER (also ideally before) adding the nutes into that fresh new water?

If not, you should pull the water and pH it to ~6.0. You could try to do it IN the res, but I've heard that is not a good idea as the pH solutions can't mix/dissolve quick enough and could harm the roots if directly exposed to it in that undissolved concentration.

Also a possibility, i recently began a dwc grow and the first time i changed my rez the same thing happened. Then i realized that my rez was now higher than it had been before the change... and i figured it was because of the roots getting less oxygen. I lowered the level and they perked... so i bought a bigger air pump and now they dont droop much even at 3 or a little more gallons. hope that helps!

IMO, certain strains will "droop" at one point or another during the photoperiod, particularly the sativa dominant strains. I have a couple of strains that do that about 8 hours into their 12 hour flowering cycle. Personally, I think it's nothing more than stem/shoot growth happening rapidly. I could be wrong, but if all you did was change out your res and run it through, I doubt you did anything wrong. You didn't do your nutrient/pH/res calculations while you were baked did you? I never recommend doing that. Trust me, I've learned the hard way. Twice before, I left the room while waiting for the tank to fill with water, gotten on the computer or sidetracked somehow, and ended up with water everywhere! I ended up spending the next 3 hours cleaning it up, and vowed to never let it happen again.