co2 undefined?

[humboldt reefer]

I just recently hooked up my acjr to my calcium reactor. My program originally ready
if ph < 6.58 then co2 off
if ph > 6.62 then co2 on
co2 is addressed to a04 on my dc8 and thats where the solenoid is plugged in.
I ran the program untill the reactor effluent reached 6.61 I impatiently changed the progam to
if ph > 6.60 then co2 on
After scrolling back through the menu to the "run" screen I noticed there is a U rather than the little square co2 symbol. So I reprogrammed it to
if ph < 6.61 then co2 off
if ph > 6.69 then co2 on
with no luck
I haved moved the plug around to different outlets on the dc8 and readdressed it accordingly but its still not working. Any ideas what I'm doing wrong here?

 

[clp]

The CO2 timer is undefined because none of the pH statements are true. As soon as the pH goes below 6.61 or above 6.69 then the CO2 timer will be defined.

Curt