Mospeadaanswered grow question 5 years ago I'm using phosphoric acid to pH down but might switch to citric acid, I'm noticing the amino acids I use have been bringing the pH down bit by bit but I need something to lower the it after silica. I could switch to using a silica dioxide but I heard citric acid doesn't stay stable or gets eaten up or something; so it'll be good enough to keep my pH down as not to cloud my solution when I'm mixing it. Yeah the purple stems are a dead give away but the P deficiency happened in veg, I'm working it back up right now. In regards to the Yucca I use it for the Saponins it contains (wetting agents), it's an aim on this grow to have as little to no salt build up and the Saponins assist in this. I don't know how I can really determine it's effectiveness for that particular use. All I know is my solution is stable and I literally add a pinch so the bag I got will last me for years...if it doesn't go out of date before then. It's a bit hard to compare grows as hydro and soil are really different. Anyways, I'm going to attempt making the concentrate tomorrow. Good luck and happy growing :)