John could have a point with the cables. Then again we should look at your signal chain. List your pedals in order as they are hooked from the guitar to the amp. You generally want to keep pedals that effect drive like Wah (always put this first), Comp, OD, Fuzz, etc up front in the chain. Try to put those in from lowest gain to highest gain order so you aren't passing all that noise through your entire signal chain when you run them. For best results run all time based effects like delay, reverb, chorus, Phaser, flanger, etc in your amps effects loop if you can. If you don't have one put them after the drive pedals. It looks like you are kind of doing this too based on the cables coming off of your board. I would keep the pitch shifter with the drive pedals out front and put the Phaser in the loop. The Polytune has two power cables running to it? That could be creating your ground loop right there because whatever you have that daisy chained to isn't isolated anymore.
Here's how I run mine.
If I'm using the Crybaby that is on the floor and is first after the guitar. Then comes my drive pedals, in this case a Nova drive which I control with a Midi Mouse, then a Musket fuzz then the amp. My effects loop send goes to my volume predal then a M108 which I use to sculpt the tone to best fit the guitar I'm using, a DE7 delay for rhythm delay, a Echo Park for lead delay & atmospheric swells (I don't run them on top of each other) a Hall of Fame reverb then back to the effects return. I normally only use this much stuff if I have a loop to work with.
For vintage tube amps without a loop I pair it down and try to keep it simple.
Everything is up front so first comes my drive pedals, SD-1, Valvecaster clean boost (The reason I run the SD1 in front of that to overdrive it's tube which is real nice), M108 EQ (I only use this if the amp needs the tweaking), Echo Park, Hall of Fame and amp. Most times I strip it down to just a boost and a reverb or a boost and a delay. The more pedals you add the more noise and problems you will get.