okay so I have been looking around at different pressurized systems and I have found that buying a regulator and a tank separately on amazon.com is the cheapest way to get a reliable system. these are the two I was looking at. I already have a diffuser end and normal aquarium air line will I need any other small parts? thanks

http://www.amazon.com/Carbon-Dioxide...TO/ref=lh_ni_t
above is the link for the CO2 tank

Amazon.com: Milwaukee Instruments Solenoid Valve, CO2 Regulator with Bubble Counter: Pet Supplies
and this is the Milwaukee Instruments regulator and bubble counter

That's pretty much it. Just make sure the line you use is CO2 safe.

I know that you can use regular airline tubing for CO2, but the co2 will basically leak through the tubing walls. You are better off using Polyethylene tubing instead. It is a lot stiffer than standard airline, but you will get better results. You can get it at Home Depot. That is where i got mine from and If I recall it was around $2.00.

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75 Gallon Planted

I just let my fish provide the co2

my .02

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fw leiden since 1979, fo salt since 1979, mixed reef 55g 2002-2009. Strong emphasis on the tank taking care of itself. Balanced with plant life, no water changes, tap water, no filters in FW. Only dosing calcium, alk, mag in marine reef tanks. http://www.aquariumforum.com/f15/my-...ods-26410.html
recent tanks (till 2009) 7 years- 10g FW leiden 7 yrs, 55g mixed reef 7, 2 yrs, 20g FW leiden, 10 g fw leiden , 29g mixed reef, current tank 55g leiden

You'd be amazed at the difference.