CAP PPM-4 CO2 CONTROLLER

This is the least expensive CO2 Controller on the market but don't be fooled, this is made by C.A.P. the leader in Hydroponic CO2 Controllers and maker of the uber popular PPM-1 and PPM-3.

Differences:

PPM-4 doesn't have a LCD display but a series of LED's to tell CO2 levels.

PPM-4 can switch up to 10 AMPS, the PPM-1 & PPM-3 only 3 AMPS (Usually not a problem unless very large 16 nozzle burners are used)

PPM-4 is preset to 1450-1500 PPM and isn't adjustable, PPM-1 & PPM-3 are fully adjustable up to 10,000 PPM for SPIDER MITE CONTROL  

The PPM-4 is the newest addition to C.A.P.’s CO2 metering lineup, offering indoor gardeners the most economic and simplest method of monitoring and controlling CO2 dispersal throughout their growing area. The simplicity of this unit will make it attractive to both the beginning hobbyist and the seasoned grower alike. Operating the PPM-4 is as easy as mounting the meter to the wall, plugging the meter into the power interface and plugging in your CO2 generator or regulator. The PPM-4 utilizes a highly visible and intuitive LED indicator display to let you know generalized CO2 levels at a glance from across the room. PPM-4 also features an easy to use calibration function.