I've had the 4 head on line for about three weeks now and has been working flawlessly. I really like that it keeps track of remaining additive and will send you an alert at the remaining value of your choice. I don't use all clear dosing containers so that's a great feature. Their app is a little finicky with connectivity if you have weak Wifi. I have a LED50 on the same app for over a year and have only had one issue where I lost Wifi for a few days and the light stayed on overnight. I just unplugged the light and plugged it in; problem solved. I've lost Wifi a few times for a few hours as Xfinity has been working on their equipment and have no issues. And it's definitely better than the Kessil App ;Vomit