Use standard PVC Primer and Cement that's used for household plumbing PVC. Make sure you use the primer as well. The primer is purple and the cement comes in either clear or gray. The primer is necessary, as it kind of melts the pipe and fittings so the glue can "soak" into it to make a weld joint. Prime and glue both pieces, put them together, give them a 1/4 twist and then hold them together for about 25 seconds, otherwise, they'll push back apart. None of this will harm your tank after it's dried. Drying takes about 15-30 minutes.
