You may be able to with a splitter. Just silicone the co2 tubing wherever they connect with some (except in the water) to seal off any leaks. You will also need the bps (bubbles per second) to be higher so that each tank has adequate co2. Get a drop checker in each tank to monitor the co2 levels to make sure the co2 doesn't overdose in either tank. Also get a bubble counter for each tank to make sure each tank is getting the same amount of co2. Make sure the tubing you are using is co2 safe tubing (airline tubing and tubing made from that material is not co2 suitable) so that you don't lose co2 from leaking through the tubing itself. Regulators are also important and necessary. They tell you when your tanks needs to be refilled, adjust the flow of co2, and some have a solenoid which allows you to plug into a timer so the system turns the co2 tank on and off by itself. For paintball tank system set ups, I used the aquatek paintball regulator. It fits right onto the tank and doesn't need any adapters or anything. It also comes with a solenoid. I got my paintball tank off of amazon everything else I needed for a paintball setup as well. The whole setup cost around $120-160. If you use the bigger tank that are measured in weight, just the tank itself could cost the same price as a paintball setup. You would also need a bigger regulator which would cost more. As for filling up the tanks, I fill them up at Dick's sporting goods for around $4-5 or so for a 24oz paintball tank. I would go for a paintball tank because they alone will last you a pretty long time. A 2.5 lb. tank would last you about 8-10 months. My paintball tank hasn't been refilled since the beginning of the year and nothing in the gauges of the regulator have gone down. It should last me at least a few more months.
