I've been using the ATI Essentials for about a year now. About 4 months ago I dismantled, moved my tank and restarted it with fresh rock and sand. Prior to that, I hadn't done a water change since starting the program. (about 6 to 8 months) I went without any water changes for the last 4 months after the move and finally did a small 10% one this last week just to give my sand a nice cleaning.
My tank has never looked better.
I'm still using the older 3 part version and will be through about July as I have a stockpile of it. I dose it off of a trio of BRS 1.1 mL pumps in their space saving jerry cans. I'm away from my tank for a week every other week, and it's super easy to have my SO do an alk test and text me the results and I can log into the Apex and adjust the dosers. Once it's dialed in it stays very steady.