Just save your money and invest in a real paintball regulator made for planted tanks. The Aquatek mini regulator is very good for the value. Having a solenoid valve will eventually save you money and practically pay for itself by not running your CO2 24/7 as you would most likely to with a DIY system. Messing with pressurized gas is something I don't take shortcuts on unless it's relatively low pressure as in a DIY yeast/sugar setup.