If you've been in the fish hobby for a short while, you probably would have been exposed to the concept of injecting CO2 into a planted tank. A brief look into it more than likely scared you away from it, more than likely due to the price! Obviously first prize would be to buy a complete kit, but after some of my own research, and experience, I've actually found this to be a pretty expensive way to do it. But because I actually didn't know what I needed, or where to get it, I obviously opted for the complete-all-in-one set up. I recently went through the experience of having to replace a leaky solenoid, and whilst i was at it, I replaced my needle valve to something more suitable to my liking. There is actually very little information out there that I have found regarding this, so I thought I'd help some of you guys get an idea of this "overwhelming" concept. There is absolutely no reason as to why people think Pressurized CO2 is only for the pro's. Yes, you will need to do your research on how much to put in, and the dangers of it, but that is your's to research. Let me explain to you what you will need: A dual guage regulator: The first guage tells you the pressure that is in the bottle, and the second guage tells you the pressure that you are releasing by opening the regulator control valve. Where can you get it? Google / Yellowpages companies that sell these dual guage regulators to the welding industry. Welding industry uses CO2 for some of the welding. I did a brief search the other day, and the average price was between R350 - R600. A solenoid: Ok, my picture is showing 2 different types. A solenoid is a "tap" that will open when the power turns on, and will close when the power turns off. Connect this to a timer, and you have it set up. The new one I purchased just over R200.00, but mine is a complete brass unit, and hugely overspec'd. Find them from suppliers of refrigeration plant equipment. Make sure it's CO2 resistant. A needle valve: Again, my pic is of 2 different types. A needle valve simply let's you fine tune the amount of CO2 you are injecting into the tank. Mine was just under R200.00. Also from refrigeration companies. Depending on the needle valve, you may need to get some adapters to fit the CO2 tubing into it. Some needle valves will come with this tho. You may also need to get some reducers... ideally have all the equipment with you as there may be differences in threads: Oh, and you will obviously need a CO2 container. I've opted for a 2kg CO2 fire extinguisher. Main reason is it is small enough to fit in the cabinet of my tank, but secondly, the price. Be cautious when buying your extinguishers. Builder's sold my first one to me at R599.00. When I wanted to refill, the suppliers were able to supply me a second bottle for R280.00. If you don't stay anywhere near a CO2 filling depot, which I bet you don't, you may need to leave your bottle with an agent for a few days before getting it back. So I have 2 bottles. When the one is empty, I send it in for filling whilst the second bottle is used. I found an agent near my office that will organize a refill for me at R25.00 per kg, plus R35 handling. Putting it all together... Simply connect the regulator to the solenoid, (taking note of the direction of the flow), and then the needle valve onto the solenoid. Put my CO2 tubing from the needle valve into the tank, and connect the regulator to the fire extinguisher bottle. (use washer). Use PTFE tape (plumber tape) on the threads. Ideally use new tape. So what is the costing roughly: Dual guage regulator: R400 (Let's work on avg price) Solenoid: R230 (Please make sure it is rated for single phase power- you may need to wire the plug on yourself.) Needle valve: R200 Adapters R50 (if needed) CO2 bottle: R280 Total cost R1160.00. Let's round that up to R1400 to cover for petrol and phone calls, cause you will be driving to a few places to get the stuff.... So even at a conservative figure of R1400.00, it's still cheaper than the cheapest regulator I've seen on the market. (SAGA @ R1499.00) AND you have the bottle!! Making the hobby just a little more affordable!