For schedule 40 pvc I just use the generic clear medium Pvc cement sold at any hardware store. I've been doing fresh tanks for about 15 years now and even the plumbing I made for them since the beginning has never leaked or broken. The pipes have all gotten brittle and yellow though
I suppose I should have added a disclaimer that I've only been doing salt for 3 years or so and am not sure if the saltwater has any degrading effects on the pvc cement. I wouldn't think so though.