Slight foam issue looking for help

[bman21]

I will post pics of my set up and everything I have. I have had this kegerator for a few years now. I have been having a foam issue the whole time. Here are the mods I did. First I adjusted the thermostat internally so I could make it colder. I am able to get down as low as 36 degrees now. I have it set between 38-40 degrees. I also made a tower cooler with a pc fan and a box to force cool air up into the tower. I

[BarryG]

So what is the foam problem?