In general when it comes to the nutrient sensitivity, all Autos are going to be more sensitive than a photo. However within autos alone some strains will also be more sensitive than others. For instance My Girl Scout Cookies, by fast buds, took nutrients just like a photo would. My seeds by Shaman genetics, not so much. Both batches where auto. There are always exceptions of the rule. Some photo strains like Dr. grinspoon need so little nitrogen, even a very light feeding can cause disaster.
Running pH'd water sounds like a good idea, but I would recommend researching rockwool, and it's properties before trying again. Some of the things I have read indicate to me it's pH fluctuates easily. Some Growers report never having any problems, and only dipping it in the water as you have described to me. On the other hand some people seem to have a constant battle and fight to keep stable pH while using rockwool. With never using it myself, or knowing much about it, my answers are rather limited in my choices. Short of doing the research for you myself, there's not a whole lot I can add to the solution. You may want to start a new thread, and be more specific in the title as far as what the problem is you believe you're experiencing. I would recommend maybe titling it something along the lines of help with rockwool and pH issues. It would attract more traffic by people who have more experience with your particular circumstances. Sorry I can't be of more assistance. I do wish you the best of luck, and will continue to read this thread and hopes of learning something myself. Take care.