k1 chamber was designed to be fed from the full siphon drain from bean animal . so water drains from tank into filter sock (first chamber ) water then flows under over and into main section of the k1 chamber thats creates a circular flow with the k1 so they can bounce off each other scraping old bacteria off as it makes its way to outside of k1 . water exits bottom of k1 chamber into open style sump with skimmer heaters and now ats . i will be honest and state i do not test po4 and nitrate anymore because color chart tests never work for me . i cannot see which color it is and often lead me to make drastic changes when it wasnt really needed . i forgor how much k1 i started with , maybe a gallon ?