Hey, glad to see you started a thread for your questions.
Let's start with
Remove the tube and poke out the little disc if it's there (it prevents backflow), then cut 1" of the hose and reattach the 1" peice.
Now we'll add a little Pump
Now hook the pump up to the 1" stub (should be about 1/2 still open)
Then follow the rest of the instruction on what to put in it. (Co2
hose, floss, sponge, whatever)
Feel free to shorten the tube by 2" if you feel it's too long (hacksaws are fun)
120 Gal SW, 150lbs Prem. Fiji, 23Gal Sump, 2x250w 15K MH, 4x65w Actinic
3 x Halichoeres Chrysus (1 surfed), 3 x Nemateleotris magnifica, 1 x Centropyge bicolor, 11 x Scarlet Hermits, 6 x Zebra Hermits, 40 x Astrea Snails, 6 x Nassarius Snails, 3 x Cerith Snails