I've made the Pvc
overflow before, they work fine but can be loud at times. it's just easier to buy a small ehopps. they are dirt cheap and work 100% (from my experience).
I'm all about the DIY, don't get me wrong, I make all my pvc
plumbing, diy lighting, diy plants, diy stands, etc...
but some things it's just easier and looks cleaner to buy the product. when I had my pvc
overflow it was just a HUGE eyesore. i'm all about the esthetics so I had to get rid of it.