Cool, My Reef Creation had the injector on the intake side of the circulation pump. That is why I was curious. That is a good point also about the acidic water. For those of you going to DIY be very carefull on how much CO2 you inject because it can melt the entire media in a short time if you are pumping too much in! These need to be checked and monitor weekly to be sure they are operating correctly. I used to watch mine daily.