Schedule 40 and 80 pvc

[JackBlasto]

So I have read that schedule 80 can't be mixed with schedule 40 PVC. I also read that the inner diameter is the same??? My question is the bulkheads my aquarium came with are schedule 80 bulkheads. Does this mean I have to do my entire PVC plumbing in schedule 80 as well? The inner diameter has threads on the bulkhead and it seems to fit when I thread a schedule 40 fitting IN it (I guess I'm using the inner diameter so it works?) I'm unsure... It seems like it fits tight and right but I don't want to cement this down the line and have it leak. Can anyone verify if this is possibly correct? Thanks.

 

[JackBlasto]

pics of 40 and 80

So here's some pics of the schedule 40 and 80. The guy at Lowes gave me the schedule 40 to fit in that bulkhead btw (which is an 80) and I'm so new to this I didn't know much better but I do know the people at Lowes sometimes don't know either. Anyway, the first pic is me putting that schedule 40 up into my schedule 80 bulkhead. The second picture is a side by side comparison of the threads on both. They appear to fit and appear identical. I don't want to learn the hard way that my eyes are wrong with a leak though. Pro advice is needed.

 

[AquaRick]

Schedule 40 and 80 can be used together. Use Christy's red hit glue. I've got sched 80 1.5" ball valves with sched 40 pipe. Sched 80 ball valves work so much better and smoother than their sched 40 counterparts. The two schedules can are interchangeable when used in low pressure systems.