Hi, I formulate all my own hair care products for my business. One of my products requires dried herbs where I use optiphen Plus to preserve the water based product. The Hibiscus herb causes the water to turn red but I noticed overtime, the red fades. I want to keep the product the same red even after it has sat for a few weeks. What do you all recommend I add to the product tht will keep it bright with out messing with the integrity of the product.