Nute coloring or root rot?

Hi all, and sorry - I've been looking at pictures of root rot, and I still can't tell whether I've got it or if it's just stained roots from nutes. Figure I ask!

Growing in DWC, using r/o water.
water temp is 64
ph has been at 5.8-6.0
steady at 300ppm
using Flora Nova Bloom

The new growth on the plants look warped, similar to how rot looks up above. For now, I've added additional Hygrozyme and lowered the chiller temp by a few more degrees. Thanks for the insight!

looks like nute stain to me. are they slimy if you touch them?

you sure your pH is good? meter calibrated? how about grow room temps?

Tent temp has been at around 70-75 (it was a little warmer last week, 75-80). Humidity according to a hygrometer I trust is at 60%.

I always worry about these cheap pH meters. I just used pH drops, it seems to match up with ~6.

At the moment, there's no smell to the roots. It's not any slimier than the roots themselves? There's a bit of a shine to the roots in general.

Flora Nova Bloom always colors the roots, they're fine..

Thanks, guys! Is it fine too, then, that the new growth is a bit warped (they look like basil leaves)? just not used to seeing anything like it.