looking bad after res change

I changed out my res about 3 hours ago. Im going from veg to bloom. I flushed out the system for About 15 minutes with tap water then I added my nutrients and balanced ph. Pump was running the whole time. Tap water was @63deg but my chiller brought it back to 70deg. Tap water ph was at 7.8 during flush and I took it down to 5.9 after adding nutrients. Im using Sensi Bloom A and B 200ml each with Voodoo Juice 75ml into 75l res. PPMs are at 690. My veg cycle was at the same ppm for the last 4 weeks. Plants looked great. Now my plants are sagging and look wilted and the leaves look like they are curling inward. What did I do???? please help.

That is a huge difference in PH from your flush to your fill. Stabilize PH and watch for changes. If nothing improves then a pic without the LED would be helpful.

Couple of thoughts...

Flush with PHed water...

If your just going into bloom most Nutes suggest a half/half mixture Grow/Bloom for the first week or two...

Hope it works out...

you shocked your roots, both are correct in saying to flush with ph'ed water.