Need Help: Anti-Syphon Valve?

[Jokes]

Where can I order or buy an Anti-syphon Valve like the one used on this DYI build?

http://www.ultimatereef.net/forums/showthread.php?t=367635&highlight=donkey

Thanks

 

[JD46]

just looks like the body of a standard airline fitting to me. Could probably use a check valve like this one

http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=10109

 

[stingythingy45]

Check valves often fail in salt water plumbing.
Why do you want a check/anti-siphon valve?

 

[Jokes]

I read some things that said that check valves and anti-syphon valves aren't the same thing.

 

[Jokes]

I built an overflow like the one in the link I posted. I need it to start the syphon for the overflow? I need to attach it to the top portion of the pVC

Check valves often fail in salt water plumbing.
Why do you want a check/anti-siphon valve?

 

[JD46]

The only reason that the fitting is there is to be able to start the syphon. If you use a check valve, and the valve works properly, you can start the syphon and the valve will prevent air from getting back into the tube and breaking the syphon. If you wanted to be extra safe, you could add a longer piece of airline tubing to the valve and after you get the syphon running you could clip the end of the tubing underneath the water surface to prevent any chance of air getting back in and breaking the vacuum.

The check valves that fail are usually the ones that are inline with the plumbing. They are often used when the sump is not big enough to handle all of the water that drains from a tank during a power outage, pump failure, etc. These are PVC fittings and are more like flapper valves and they do get crudded up over time and fail more often than not.

The airline duckbill valves, I believe, are pretty reliable.

Another option could be to use a micro ball valve although I am not sure how air tight they are.

 

[JohnK]

But going back to the beginning....

regardless of many youtube videos claiming the contrary, these PVC overflow systems are FAR from ideal and should be avoided by any serious reefkeeper. The negatives are countless, but the two biggest issues are; Total lack of surface skimming, and lack of reliablity.

Do it right in the first place, drill your tank and insall a proper overflow. If you want help on doing it right, just ask. There are plenty of us locals that can help you. If you set up one of these BS PVC overflow systems be warned, you ARE invoking the full power of Murphy's Law!