The undertow 25 R is a quality bottom fed DWC system and is deffinetly a fan favorite and will be even more now as we have added a couple additional features that are not pictured. Now with more movability with separate feed lines from reservoir. Want more dissolved oxygen? Who doesn't..! Now you get it with now standard 90° inlet fitting creating more more waves which does 2 things, more DO2  and keeps a more balanced mixing of your nutrients. Draining the system while leaving your reservoir intact or even change out one OR  all three with the ease of a couple valves being opened or closed. while a upgraded water pump giving you more GPH