Curling leaves

Usually the claw would mean excess nitro from what I’ve read. This is my first DWC bucket. She’s about 5 weeks old and started curling under about a week ago. Highest ppm she’s taken was the 700’s. She always drinks more water than nutes or the water is evaporating quicker. Feeding gh trio, flora blend, Hydroguard, silica, cal mag.

So thinking excess nitro I flushed pure ro water for three days. She looks the same. The leaves aren’t meaty like I’d expect. They seem thinner but not dying. So if it’s not nitro then what else could it be. Reservoir is 70° max.

It does look like slight claw. A pic of the whole plant would be better. I would just skip the GH grow for a while. Some strains are just nute sensitive.