Help My plant is dying and I dont Know why!

I have had my plant in veg for 2.5 months in a 5 gallon dwc. im using gh floroduo, calmag and hygrozyme. i started noticing problems about a week or so ago with some random brown spots like the one in pic 1. next the plant started to droop and now all new growth is coming in deformed/clawed and the fan leaves are ranging from dark green to palish with little brown spots.

After looking online and not being able to find the problem i set up a bigger res from 5 gal bucket to a 10 gal tote with an extra airstone. I also realised that ive been giving the plant distilled water for the last 2 weeks (before that i was using tap and everything looked great) so when i set up the new res i went back to using tap water. i also havent given any calmag in awhile so i added that. my ppm has been just under 700 and my ph has been 5.8 - 6.1.

Is there something im missing?

BTW my roots look amazing bright white and firm - however i was thinking maybe they had out grown the 5 gal bucket? they were really piling up

I think getting them on the cal/mag was the right move.

well, if they were fine until you made the water change, change back...

I could be wrong but in some of the pictures it looks like something is eating your leaves

There is cal is norm tap water

You've got some slight nitrogen toxicity going i.e deep dark green leaves and the clawing. Also the burnt tips indicates over nuting. Im not a hydro guy but I would change the res, and add nutes at a lower dosage than what ever it is you have been doing.