If he's peeing that frequently, I'd have him looked at, and switch him to a Urinary tract health food. Purina makes one. Older neutered male cats have big problems with bladder stones that at the very least, make them think they have to pee all the time, because the stones take up the volume of the bladder... but it can be very painful and seriously life threatening when they pass the stones. It's all correctable with diet, something wrong with the PH of regular processed cat chow.
I'm looking at the cat's food he came with. It's purina ONE special care for adult cats. It says advanced hairball formula but nothing about urinary. This isn't what you were talking about, is it?