I have a ctf kent 24gpd unit just got the stuff in the mail to turn this into a tfc unit 50 gpd, my question is were do you put the flow restrictor on the intake blue line or waste line orange. lots of waste water very little good water, at this rate it will be 2 days before I get 50gals. One more question I have black spots under the sand bed about the size of a dime. :twisted: