The posts above are correct. This is a DIY reactor similar to that designed by DJ88 on reefcentral. I have one very very similar.
In picture #1:
- the john guest fitting on the side of the reactor (purple tie) is the outlet where water (with disolved calcium) leaves the reactor. This is often called the "effluent" outlet
- The two larger PVC pipes on the bottom need to tie into a pump that circulates the water within the reactor. A pump similar to a mag3 would work fine. When you tie in this pump the inlet connects to the left and the outlet connects to the right. (i.e. the left side of the reactor pictured is where the outlet is, the right column is where the water gets circulated into the reactor.
- On the left PVC (blue tie) there is a fitting with two john guest fittings poking out the side (red tie and yellow tie). One of them connects to the top of the skimmer to recirculate the air that may collect there, the other is inflow from the tank.
Photo #2 shows a close up of the bubble counter.
- Co2 from a Co2 tank goes into the bottom (yellow tie) and then the top is the exit (green tie).
- Once the Co2 exits the bubble counter, it needs to join the tubing from the tank supplying water to the reactor. This is best accomplished with a "T".
- The bubble counter should be partially filled with RO water so you can see the bubbles.
Photo #3 is an overall photo
So overall you CO2 in from CO2 tank, through the bubble counter, then joining inflow from the tank with a john guest "T" and then join the reactor either at the red tie or yellow tie on the left side. The top of the reactor is connected to the other tie at this same location. Water circulates in the reactor, and then exits at the other john guest fitting on the left side of the reactor and tubing should go back to the tank.
Lastly, it is best to regulate the water flow into the tank by putting a gate valve or ball valve so you can slow down or open up the flow into the reactor.
If you are ever near downtown and want to see mine in action, let me know.
Hope that helps.
Mat