Blake wrote:

I have a 155g tank that I'm getting ready to re-plant. I'm going to be
adding a CO2 system to it and am considering a PH controller. I was
wondering if anyone had any advice as to:

1) Whether this is really necessary

What is your objective for installing a pH controller? Asked another way,
what is your reason to controlling your pH to within 0.02, 24 hours/day?