I started feeding my house plants in the front yard .25 tsp / gallon following the directions on the package and they're all doing really good. Although I think it leeches to fast in my garden's soil to keep using it there, but I do like it for my container plants. I haven't burned any plants yet; knock on wood. It lowers pH, but in my case it's not lowering it enough. Support is hit or miss too. They answered all my initial questions, but never responded to several follow up emails. To be fair, I never bothered to call them.
I loved that Hydroponic Research didn't make me pay for shipping on their free sample. And they didn't require it to be delivered to a hydro store. Also the free sample I got was actually their one pound tub, which retails on their website for $19.95. So even if all it does it equal my existing nutrients. I'm stoked. It's free fertilizer!