The Specs:
This whole system is made up of 3 soda/water bottles, your average air tubing, 1 check valve, 1 adjustable flow valve, with the CO2 piped into the hagen elite mini filter.
The setup:
I have your basic soda bottle CO2 Generator (we will call it bottle #1), using: 3/4 bottle of water, 1/2 cup sugar, 1/8 teaspoon yeast, and a pinch of baking soda (supposed to help stabilize internal ph of bottle). I drilled a hole in the bottle cap and ran the air tubing just through the middle only sticking out 1/4" on the inside, and glued in place with gorilla glue (gorilla glue was on hand and was used to cut down on costs). With the ingredients mixed and the bottle capped, I then heated up a pot of water to about 105 degrees to "kickstart" the yeast,(used a candy making thermometer). I then placed the bottle and contents into the pan of warmed water for about 10-15 min.
The CO2 from the generator is piped to bottle #2. Bottle #2 is what some would call my "gas collector"/"bubble counter". This is basically just a bottle filled up 3/4 with water, with 2 airline tubes ran through the cap. One tube is sticking into the water, the other is not. This allows you to count to see how many co2 bubbles are being made within a certain period of time. Mine makes about 1 bubble every 20 seconds, so you can say 3 bubbles per minute. You want the tube coming from bottle #1 sticking down into the water. The OTHER tube that is not sticking into the water, goes from #2 and to a "T" fitting.
For the other two parts of the "T" fitting, one tube goes to a check valve, then the hagan filter, which diffuses the CO2 as it circulates water through the aquarium. The other end goes to my "blowoff" valve and bottle. I decided to incorporate the blowoff valve to be able to control the bubble pressure and to have the ability to turn the rig "off" at night. The valve is attached to some tubing which goes into the water bottle, filled with water so that you can visually see how much CO2 you are "bleeding" off of the system. I just poked some holes in the bottle cap, to let out excess pressure.
I will be making a "paint" diagram so this is easier to visualize, my pictures and explanation might make it seem confusing.