Return line check valve

[StartrTank]

I'm in the process of plumbing my tank and thought it would be a good idea to put an in-line check valve on the return lines from my sump. Would a check valve with a sping loaded poppet have too much negative effect on the flow rate? Would I be better off using a "cheaper" made valve that uses a flap with no spring?

 

[E Rosewater]

It's far better to plumb in a way that wouldn't require one. They will have a negative effect and are prone to failure.

 

[sleepydoc]

+1

Check valves are notoriously unreliable, making them pretty much pointless.

 

[tkeracer619]

saltwater + check valve = wet floor.

 

[hijinks]

It's better to keep enough room in the sump to handle the back flow from the display tank

 

[elmatth1]

Yes, you want one with no spring. That said, they will restrict flow considerably, so what I would recommend is to step up your plumbing to one size larger at the check valve, then return it to normal after. You do want to allow for enough room in your sump though for normal backflow should the check valve fail, which everyone is apparently confident will happen at some point.

 

[StartrTank]

Ok thanks everyone. Guess I'll spend some more time on the plumbing to eliminate the need for one

 

[sleepydoc]

That's the best way. If you think about it, any safety or emergency backup device that needs regular maintenance to work properly probably isn't the best choice.

 

[tkeracer619]

We had one of those clear bluish pvc check valves split at the seam on the output of a hammerhead return for a 1500g display.

Didn't really make a mess... at all... /end sarcasm.

 

[E Rosewater]

Is there a significant distance between your sump and your tank?

Are your return lines plumbed through your overflow?

 

[StartrTank]

E Rosewater, no they are not plumbed through my overflow.

I have a 55 gal acrylic hex tank. It has a cutout for the overflow, two holes drilled for my return lines and the main center opening for feeding, etc..

I would est. there to be approx 4' of rise from my return pump in my sump to the top of my display tank. I have 1" pvc running about 2-1/2' from my Eheim 5000 before i have it split running two 1" pipes to the two return holes in my display tank. I currently have lockline entering my tank through the return bulkheads but I'm reading a lot of people suggesting open pvc instead to cut down on restriction, so I'll probably remove them and add a bit of pvc.

Can anyone suggest an acceptable black paint to use on the pvc that will be safe in the water?

 

[amond003]

Krylon Fusion

 

[intyme]

It's far better to plumb in a way that wouldn't require one. They will have a negative effect and are prone to failure.

Not to hijack.... What's the proper way?

 

[E Rosewater]

Have the return lines come to the top of the tank and just below water level drill a small hole in the return line to act as a siphon break

 

[SGT_York]

Have at least one return outlet that is slightly below the waterline so when the pump goes off the outlet is exposed to air.

Also stay away from any metal inside your plumbing. The cheaper checkvalves use a lower grade stainless steel spring that will leach zinc into the water column.

 

[uncleof6]

Not to hijack.... What's the proper way?

The proper way is to have enough spare volume in the sump to hold all power out drain down. No device, or anti siphon holes, can be trusted. If you don't have enough room, get a bigger sump. Sumps should only run ~ half full, in normal operation, and with the return outlet within an inch of the water surface in the tank, anti-siphon holes are pointless and the drain down is not huge; it is easy to calculate how much room you need in the sump. In reality, power out drain down is seldom an issue, unless you are breaking the rules.