Check valve and unions

[steallife904]

how many of you use check valves as well as unions in your plumbing. I am working on my plumbing and was wondering if i should install a check valve on my return line and if i should use some unions? Only concern with either of them is if they will fail. Specifically on the unions if the will leak?

[ericarenee]

Sometimes the more Thoughtfully placed unions the better..
Check valves on a Marine tank is a Failure to happen.

Say Absolutely yes on unions

Check valves 120% NO NO AND NO...

[gone fishin]

I use some unions and have not had issues with leaking. I have an external return pump so unions make it easy to remove for occasional cleaning. I don't use a check valve.

[steallife904]

when threading the unions together do you use plumbers tape /thread tape (whatever its called) on the threads of the unions?

[DaveMorris]

As long as the rubber O ring is still in the union, they won't leak if they are tight. I like to use unions anywhere that I may need to move something such as on either side of my return pump. There I actually use union ball valves. Makes it easy to remove the pump for cleaning. You do not need to use thread tape because water never hits the threads anyway. The internal O ring takes care of that. When you buy them, make sure you unscrew them to check that the O ring is still there. As far as check valves go, if your plumbing is planned out correctly, you should not need them at all. They will end up leaking internally which defeats their purpose and this will undoubtedly happen at the most inopportune time.

[BlackTip]

I use one union, I wish I had room to use more. No check valves. You won't need them, if your system is designed right.

[JMorris271]

For placement of unions, think hypothetically what you would do if this or that happens and will require something to be removed.

[steallife904]

ok so drop the check valve... im thinking it sounds like a good idea to add at least 1 union on each line for a just in case (1 on both drain line and 1 on each return line). Think i am going to order them off bulk reef supply. Would think those should be good ones???

[kmbyrnes]

Just get them from a big box. Much cheaper.

[CStrickland]

Big box. Make sure to get the all pvc kind, no brass. When you place them, think if the unions as something to make it easy to get in there to clear the line, like the trap under your sinks, and also anyplace you might want to move stuff, where you'd rather not cut it out. True unions can save money cause you can unscrew and use in diff places instead of cutting it off and buying a new one if you change things up.

[Isaacs55]

No need for a check valve if you plan your return line right. Meaning not too low to where your bulkhead is like no more than 5- 6 inches under the water line of your DT, but at least 2 inches from the top of your trim on the tank or if rimless then 3 inches...
And if course never have your loc line fully submerged under water.
I have the end of my loc line submerged but not more than a half inch.

[snorvich]

Sometimes the more Thoughtfully placed unions the better..
Check valves on a Marine tank is a Failure to happen.

Say Absolutely yes on unions

Check valves 120% NO NO AND NO...

What she said.