I just put 3 big blue penteks on my POE for our house. Now I’m feeding my rodi AFTER those. Seeing about 120tds. I hope that extends the life of my filters as I tend to make a good bit of water. I also placed the 20” chloramine buster from pentek at the second filter as my municipality uses chloramines. Oddly enough, once I added that I saw my first outbreak of cyano.