Yep, Great article and research....I'm not going to argue any of their points. Great Pics of Cover also....most of my posts cover the use and difference of dense cover for habitat, etc., and honey hole cover or attractors.
Some White PVC does have compounds for plumbing jobs...but I think it is marked.
I know that all of the White PVC that we have used and went back to pull it up, all had fantastic colonies of Algae. All of ours was sand deeply with 60 grit and our water is extremely fertile!