Aqua Ionizer Deluxe 9.0 is one of the best alkaline filters with all the essential and high-end features present. It comes with an adjustable pH range and seven different water modes from which you can choose effectively. Additionally, we found this product particularly interesting because of its ability to reintroduce minerals. Lastly, the self-cleaning mechanism, FDA-approved construction, and BPA-free plastic make it stand among others.