My current DIY project is a DIY media reactor, carbon chamber basically. I was curious if it makes more sense to put it after my main filter An Eheim 2217 or after my second filter an Eheim 2215? I currently am running both filters with Biohome Ultimate on a 120 gallon tank. I have 2 large pieces of driftwood that I soaked for almost a month changing the water everyday that still are leaching tannins into the water hence the reason for the carbon filter.
Full tank shot