Brown edges fan leaves

I think you have answered your own question! "has been happening since adding rhino-k" The older leaves fading slowly yellow during flowering is normal, but yellowing and burnt black edges certainly isn't. I would be halving the dose of rhino-k as a start and see if that reduces the damage. Also adding some dedicate bloom nutrients may help too, Bio Diesel is really only a "tonic" and not a complete fertilizer, so your plant is not really getting a balanced diet, which will limit flower health and growth. Hope this helps,........ Organoman.

You have nutrition burn. Brown curling up tips is too much nutrition. I am have same issues to at times. Your looks a bit more agressive. Good luck.