Hiya
You will find this in the pH control screen of the profilux pc software, i am assuming you are accessing the ProfiLux from your pc?
You then set the corresponding modes in this screen
For example you would set the maintained reading to 6.5 with a hysterix of 0.1 and set to switch on when the reading goes high.
I will try and find some screen shots for you, but please can you confirm you are viewing the settings via a pc, this will help in giving you advise.
Regards
Michael
www.aqua-digital.com