They said they do not recommend GFCI outlets for the PC4s since it can cause damage (not sure how -maybe Alton can explain) to the PC4.

I can not believe they recommend not using GFCI's, with that statement here is a scenero for everyone. Someone follows there advice and then gets electrocuted(dead) because of a faulty piece of equipment. The persons family then follows up with the letter or email that DA recommended not to use GFCI's and sues DA. If I am sitting on that jury, it would be pretty easy win for the family.

One other piece of advice before I go away, so many times I see aquarist have there controllers mounted in there cabinets above there sumps and skimmers. My question is "would you store your laptop computer in your aquarium stand every night?"