Apparently, their system is like a denitrification filter. From what I can tell, they just turned a sump into a Calcium reactor. They claim that using their system, you don't need to do water changes or dose elements. What's your opinion on them? Personally, I think the "no water changes" claim is a little outlandish; I'm not sure their denitrification system can outpace the nutrients produced by a standard tank.