Co2 line from your regulator goes into a check valve, then into the bubble counter, at the top, blue is effluent out, Feed water line should be connected to the barb fitting where the circulation pump connects to or john guest fitting that is on the pvc part. the black tubing for the circulation pump should come with plastic clips that tighten around the tube and barbs.
I have a 612 x 2 so it is a little different but mostly the same. I use a versa to pull effluent out at 80ml min, just enough so that the effluent is at a constant stream of drips without any pause. Set your co2 pressure to around 6-10 ( doesn't have to be exact) and start at a ph of 7.5ph on 7.4ph off. Check your alk before you make any changes and 24 hours after. My tank only has maybe 12 acro frags and a couple lps and my uptake is around .3 dkH per day, ph range stays between 7.4-7.3ph and alk is stable at 8. As things grow or if I add more coral, I will leave everything alone and just lower the pH bye .5pH at a time. Hope this helps.
