Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Design Flaws.. can't prime

I don't know why no one talks about it, but this filter is flawed in its design. There are a lot of forum thread on-line talking about the fact that this thing is a pain to prime. Or if it even pumps at all. Unfortunately I found out the hard way, because I learned only after I've purchased one. After 2 hours of inspecting every single o-ring, and filter component and trying to get it to pump correctly I've given up. Some forum postings suggest that the product may be defective, but if there are so many people with the same problem, there is something wrong with the product, not the users. I strongly suggest you read about this in other sites before you decide to purchase. As for me, this one is going back to the seller.