I have very shitty dial up so can't download your photos....they're too big or something.....but overfert is the very first thing that comes to mind. However....a ppm of 500 SHOULDN:T be too much for your plants.

Revised: The Complete Guide To Sick Plants,pH and Pest Troubles - PlanetGanja.com

I think probably part of your issue is the rockwool and it's associated overwatering and/or ph issues.

I've never heard of Superbrand Grow Aqua so can't help you with any advice on it.

Good luck.
Weedhound Reviewed by Weedhound on . some leaves thin, curled-upward, browning edges Hello all, I'm a newbie, on my first grow. I just switched from 24-on to 12/12 yesterday (600w HPS) , and today when the lights came on I noticed that about half my plants have varying degrees of a leaf issue that I'm unsure about. Some of the leaves have begun to curl upwards along the edges, with accompanying browning and a thin appearance. There's also a bit of yellowing on all of the plants, which I was told was signs of growth and not to worry. But this is new, and I'm concerned and Rating: 5