Hi, Wondering if you can offer any advice on this subject. I'm trying to set up an experiment using hydrangeas. I already have the pink and blue hydrangeas, but I want to demonstrate using a soil probe that the soil ph is different in the pink and blue flowers. In the pot for the blue hydrangea I am using an azalea soil, a soil acidifier (30%sulfur), cedar mulch and distilled water (the water here is alkaline). There is virtually no difference in the ph. I know it takes time to change the ph, but can you recommend a product to change the acidity today? I am wondering if liquid iron would work? I'm writing to you because I lived in OR until recently. Thank you Debra Scharlay