Bubble CO2 through water and you get carbonic acid. Keep em separate. Also the best way to go would be to release the pressure into the coil, have a very tiny hole to release the gas over time onto the plants. Put it into the coil in one blast for the greatest effect. FYI thats how air conditioners work but they have a condenser to compress the gas again so its a cycle....you got a cold and hot side. You really dont need a regulator just a solenoid on a timer as long as the pipe can hold the pressure of the bottle.