I've quoted your questions and replied below each one.
>I'm wondering, how long would a 20 oz paint ball CO2 tank would last me? <
A 20 oz tank on my 75 bow tank was last filled Dec 9th. The gauge still reads 875 psig at 72F. Its at 2-3 bubbles per second through water into a DIY external reactor / heater chamber. Similar in operation to ones Rex makes. My lighting timer switches a solenoid on for 7 hours a day.
>If it would last me around 1 month, I'd be fine with that. <
No worries, even without a solenoid, at about $30-40, you'll save you more in time and refill costs. Considering even $10 for a 20oz refill, it'll return the investment within a few months. Not to mention the your time, driving, and the cost of gas to get it filled.
>"The specs on my desired system are pretty simple, standard needle valve,
dual gauge pressure regulator, Rhinox 2000, and some CO2 resistant tubing.<
You'll also need at least one check valve, a bubble counter and I'd highly recommend a solenoid.
A check valve will prevent filling your CO2 equipment with water and destroying it, not to mention the possiblity of emptying the aquarium onto the floor. Depending on the bubble counter design you may need another between it and the regulator to prevent getting the water in the counter into the regulator.
A 20 paintball tank fits nicely in a bicycle water bottle holder. You can mount it up higher inside the stand and make it fit a bit easier.
Dual gauges are nice, but not really necesary. The high pressure gauge will tell you when the bottle is nearing empty. Once the low pressure is set, you realy don't have to change it much. The bubble counter after the needle valve is all that you really need. Just adjust regulator pressure until you are able to control the bubble rate well with the needle valve.
>...will a standard pressure regulator fit on it?<
Well, yes and no. You need an inert gas regulator rated at 2000psi or so. Oxygen, helium, nitrogen, argon, and CO2 are common inert gas regulators. A standard sized CO2 bottle fitting is too large for the paintball tank, but you can adapt it. Remove the big bottle fitting and screw in a nipple and a paintball remote or bottle fitting. I used a small argon welding regulator I already had, a high pressure brass nipple and scrounged and modified a fitting off a friends broken paintball marker.
That is a big regulator, almost 1/3 the size of a 20 oz tank. It also appears to be a cheap Chinese knock off. I wouldn't recomend it.
Last edited by madman280; 03-10-2007 at 02:26 PM.
Reason: spelling and grammer :-S