No, nobody here to told me they used DE. It was the pool guy, both realtors (mine and the seller's) and a few other people. I didn't know any better so I took their word for it. I was going to buy some DE soon too. I did kind of wonder why my filters didn't look like the ones on youtube when I was looking up on how to service them.

I saw that the Unicels are almost half an inch larger in diameter so I opened and looked inside the housing and there's plenty of clearance. I ordered a set from Amazon.