Union PVC on return lines? Handle the pressure? Other options?

I am sort of following what you are saying. Not sure what SCH40 PVC you found with threads. Are the insides of your bulkheads threaded or slip?

I have unions on both of my returns and drains for my 120 gallon RR and I am using an Iwaki WMD-40RLXT which has 1200 GPH and it is working great. I was at the Cedar Rapids Spring tank Tour and saw a lot less water flow coming out of some of the awesome tanks, but those tanks also had more powerhead water movement than mine.

Your Iwaki looks like it is rated at 1080 GPH, and depending on how much powerhead movement you plan to have, even losing some GPH from the pump through some unions won't hurt too much.


Another option is to get the next size up union. You would need to get the correct reducers to connect the later union to the smaller pipe, but your flow wouldn't be hindered.

Of course, you are still going from 1" down to 3/4" through the return pipe shown in your picture anyway.

Not sure if any of that information helps or not. Sorry if it doesn't.

 

Fyi those were new bulkheads so dont wonder how it didnt leak lol. Unions hold the pressure just fine. I have a union ball valve a foot off my pump pushing 4000gph and its nothing. Good to see you finally setting this bad boy up! If you need any help jus give me a shout after all your basically down the road.

 

David we didnt those were new bheads and we never got around to plumbing it.

 

The previous owner had cut the plumbing right at the bhead so we couldnt use a coupler and go with it. Wasnt much of a favor lol.