Wow thats pretty neat lol. i dont want to do anything like that i just want to use the tank water to water soil plants with i dont think i wanna recycle the water back into my tank after the plants clean it lol that requires a hydro setup anyways. What do you meen about what the fish eats? would what type of foods fed to them make a huge differnce i mean it all comes out as the same types of waste in the end Ammonia Nitrite Nitrate right?? and as far as additives go do you mean like any medicines used for sick fish and such? what if i filtered the tank water through carbon on the way into the bucket for watering that would strip most unwanted additives out right?