Backsiphoning

1/4 inch holes are too big. You don't want much water to come out of em. I just use a small hole maybe 1/16" or 1/8" right at or JUST below the surface of the water, that way the only water that back siphons will be whats already in the pipe and non from the DT. I'm using 3/4" return also.

 

Thank you very much. did you drill only one hole or more? Thanks again everyone who responded

 

You can put more than one. PG had a pretty good point about a snail blocking it. Might be unlikely, but hey, it could happen. Better safe than sorry.

 

Ya point taken. I just dont want too much water coming out of the holes.

 

Better to be safe then sorry reefdaily... Just drill a 1/8 hole as backup...

Make sure you have extra room in your sump... turn off the return and keep filling your DT until the water level in your sump is just below maximum... Mark that line on the sump as MAX FILL... Then you'll know if power goes out, you wont overflow the sump...

GL im working on my sump also

 

I guess I could drill a hole just in case. Always nice to have a back up!

 

There won't be much coming out of the holes at all. Water will always flow along the path of less resistance, and that will be straight along past the holes to the one giant hole at the end of the pipe You just want to make sure to put the holes under water, or the rushing water will actually suck air in and cause bubbles and even noise.

 

If its man made it will fail eventually. I work where we have hundreds and hundreds of check valves. ranging in price up to thousands and thousands of dollers. they ALL fail eventually. not trying to worry you but if there is a better way to do it and not have to depend on one I would go that route,

 

Very nice comment on the second hole. K+

 

IME 1/8" is too small. I started out with holes that small and they would fill up with algae and would not stop the backsiphon fast enough. Even with 1/4" holes very little water comes out of them when operating normally. The bigger the whole under the surface the faster your siphon will break in a power outage.