Do you use check valves?

[KH971]

As the question is does anyone use them? Or do you just drill a hole to break siphon?

 

[Dr. Chek]

are you talking about back-flow preventers?
I do not, there was a small hole drilled just above the output into the tank. it works perfectly....

 

[elephen]

1.5-2" check valves get pricey. I just drill a hole right below the water level to break the siphon.

 

[Gwoardnog]

I have one installed but it doesn't work anymore (not sure if it really ever worked). Er on the safe side and go for the break siphon hole.

 

[sjm817]

I use a check valve and siphon break holes ( I dont trust either)

 

[Entropy]

I don't like anything that causes additional back pressure. I just use syphon break holes. My return nozzles are high enough in the tank that even if the syphon hole fails, the tank will not drain enough to expose any corals, or overflow my sump.

 

[sjm817]

"Unless you really need every last drop of flow out of the return pump", ---I would not worry about the check valve back pressure. Its minimal. Other things such as undersized plumbing, elbows, etc contribute more to back pressure.

 

[javajaws]

I don't use either. My sump is large enough to hold all the water that drains from the top of the tank down to the top of the highest return nozzle. 0 chance for failure assuming I never fill my sump above my theoretical "max fill" line...and even then I've got an overflow drain on my sump that goes outside.

 

[fishylad]

I had a check and removed it, resticted too much flow, not to mention that it quit working. I go with the siphon brake now. I have enough room in my sump in case a snail or some thing blocks the break so I don't get all wet

 

[AZDesertRat]

Check valves do create flow restrictions. Most aquarium pumps are not designed for much head pressure so any restriction at all is major. In drinking water systems a single check valve can add about 5 pounds of back pressure or head on a pump. That is equivalent to 11.5 feet lift which maxes out most pumps.
They will fail and at the most inopportune time and cause you headaches down the road. Simple siphon breaks or air gaps are a much better choice and do not add back pressure.

 

[sjm817]

I dont know about drinking water check valves, but the True Union Spears check valves I've used have very little flow restriction. I didn't see any significant difference in flow after installation. Adding 11' of head would have been very noticeable.

FWIW, The head loss calc shows a 1" swing check valve less than 1' of head

 

[AZDesertRat]

All check valves require energy to move the ball, clapper, spring and/or or disc as well as the fact water has to change directions to flow around the obstacle. Coupled with the fact they are not reliable in aquatic conditions why use one when a simple air break will suffice and be more reliable?

 

[Sm0kin]

check valves are good for keeping a pump primed.

 

[sjm817]

Mine has worked perfectly for over a year. I like it because it minimizes the amount the display level drops when I turn off the return pump. Very little backflow to the sump. If it ever did fail, then the siphon breaks would kick in when the water dropped low enough. There is no downside.

The spears valve is wider than the input/output. The flow restriction is very minimal. Like I posted. before/after flow difference was negligible. I kind of go by real world testing over theoretical results.

I'd say more people are losing way more flow from their returns from undersized plumbing than the tiny amount of a good quality check valve.

 

[AZDesertRat]

I would think 31 years of water and wastewater operations qualifies as real world experience. I have probably repaired or replaced more check valves than you have seen in your lifetime. I am not an engineer and do not rely on theory but am an operator and correct engineers mistakes quite often. Check valves do cause restrictions and power costs and pump efficiency testing proves it in the real world.

 

[sjm817]

Funny, I dont recall you being here when I tested this setup. I can tell you for a fact I didn't get anywhere near a 11.5' equivalent increase in head pressure. That is simply ridiculous.

As a matter of fact, the head loss calc shows I would have 0 GPH by adding that much head. Funny, but last I looked at my system, there is a lot water flowing through it.

There are a lot of things that decrease flow. Poor/undersized plumbing, union valves, couplings, elbows, etc. They are used for convenience to make the owners system easier to work with or more aesthetically pleasing. A good check valve adds maybe a small amount of loss, nothing major, or in my case even noticeable.

 

[AZDesertRat]

Buy or rent a watt hour meter and do some power calculations. It will prove you wrong. You can also put a rotameter on it and see the flow loss in inches. I assure you there is a loss.

 

[sjm817]

I dont need a meter to see the difference. I can tell from display Vs sump levels, and I run a Deltec Direct fed skimmer which is fed off the overflow. The flow through it is very exact @ 160 GPH. A small change in flow will require a adjustment.

BTW, you are complaining about the minuscule flow loss from a check valve and you run a SCWD?

Now that is too funny. The only thing that adds more flow restriction is a cork.