Plumbing Drain Help

[ReefChasing]

I recently purchased a new return pump because my old one was dying. Unfortunately I can't adjust the power on my new pump to more than 15% without a siphon occurring in the drain going down into my sump. When this happens it is really loud and there is slurping noise once the siphon breaks.

I'm not sure how to attach an image with the size limits here so I'll do my best to explain what I'm working with. I have a pvc drain pipe the shape of a cane behind my overflow box. There is a small hole about a quarter inch diameter drilled horizontally through it at the waterline level which I believe is supposed to be the siphon break. But when the pump is on a higher power the water goes above the small hole and a siphon is created until that sucks so much water down that the water level in the overflow box goes down and the siphon breaks. This then repeats over and over again.

Should I try to drill some holes in the top of my drain pipe that looks like a cane to prevent a siphon from happening or it least limit its power?

 

[mcgyvr]

You simply are pushing too much through it..
Keep the pump turned down or redo the entire plumbing to support the desired GPH..

Unless you redo your plumbing you are risking a potential overflow by running more GPH than your stuff can handle..

 

[ReefChasing]

It doesn't make sense though. The pump is supposed to be rated at 1600 gph with 5 ft of head. I have two 45 degree elbows in the return as well so that's a loss of 100 gph. That would put me at 1500 gph max at full power.

My drain is 1.25" so that should be 1000 gph right? That would mean I should at least be able to run the pump at 50% power.

 

[mcgyvr]

My drain is 1.25" so that should be 1000 gph right? That would mean I should at least be able to run the pump at 50% power.

makes sense to me..
As you found out its able to drain whatever you were pushing through it (once it was a full siphon).. You didn't flood the floor right?
Its just not going to do so as an open channel...

 

[ReefChasing]

No, it didn't flood the floor. I guess I just figured I'd be able to run the pump at around 50% with its gph rating and the size of my drain pipe.

At least it will be a little quieter running at a lower setting and I won't be using as much electricity(flow not controlled by a valve).

Maybe I'll add some cheato in the sump with the low flow.

 

[Breadman03]

It doesn't make sense though. The pump is supposed to be rated at 1600 gph with 5 ft of head. I have two 45 degree elbows in the return as well so that's a loss of 100 gph. That would put me at 1500 gph max at full power.

My drain is 1.25" so that should be 1000 gph right? That would mean I should at least be able to run the pump at 50% power.

The pipe may be 1.25", but it is likely much smaller where it goes through the bottom of the tank. You are running a Durso standpipe by your description. They work, but only at fairly low flow rates.

If you want a high-flow system, look up Herbie and BeanAnimal drains. The Herbie is easier to set up because it only requires two holes, with your return going over the top of the tank rim, at the cost of being a little more difficult to tune and being a little less failure resistant.