What size bulkhead?

[Adam Gilbert]

Getting ready to plumb my first tank and wondering if I'll be able to get enough flow. I have a 90 gal tank with predrilled holes on the bottom left that are 1.75" diameter. From what I'm reading, I'll need a 3/4" bulkhead (https://www.bulkreefsupply.com/schedule-80-bulkhead-thread-x-thread.html) for that size hole. I'll be running the Vectra L2 return pump (overkill, I know, but I got it for a steal) and aiming for a flow of 1200 GPH.

I was planning on using SCH 80 1.25" pipe but what I'm reading is that your bulkheads should be 2x the size of your pipe. Is this correct? If so, I'll need to plug the existing holes and redrill?

Thanks in advance. I'm new to the hobby and trying to avoid a water mess on my hardwood floors...

 

[dreamcatcherr9]

I’m sure someone who really knows what they doing will answer. I’m curious too. I’d think from my research you can use 1.5” pvc. Just enlarge and reduce the line as needed (?). Let’s see what the experts say.

 

[JoshH]

If your holes are 1 3/4" big the largest bulkhead you can fit in there is a 1" schedule 40 or if you're looking at schedule 80, as you say, 3/4". Bulkheads only need to match the pipe that is going through them so if you're wanting a 1 1/4" pipe for your drain (which I would avoid and stick with either 1" or 1 1/2") you need a 1 1/4" bulkhead. The hole in the glass however will be almost double the pipe size if you're looking at schedule 80 bulkheads. Not sure on the 1 1/4" but I know a Schedule 80 1" bullhead needs a 2 1/8" hole drilled in the glass to fit.