Problem with Durso Standpipe gushing water

[mskvarenina]

From time to time, seemly at random my Durso Standpipe will start draining funny. What happens is it will start going into a drain cycle where there will be a rush of water into the sump, followed by no water, then a bug gush of water again. This may go on for many minutes before it stabilizes itself and normal flow resumes. The big problem is the big rush of water nearly overflows the input section of the sump and water sprays everywhere.

Is this a common occurrence and do you have any suggestions on how to address it?

[EllisJuan]

Make the hole in the top of the durso bigger or throttle back your return pump.

[drew2007]

+1 try and throttle back your return pump. That usually happens when your trying to push too much water through the durso.

[sirreal63]

It is flushing, which means you are putting more water into the drain than it can properly drain and momentarily goes into a siphon. Slow down the flow and it should stop flushing. Making the air hole bigger may or may not help, slowing the flow from the return will work.

[mskvarenina]

Siphoning is a good term for it. I've posted a video to YouTube showing both the overflow and sump side. The video is here: http://youtu.be/WpQVRR9XcDY

Any ideas why this would just start siphoning randomly? The tank will run fine for days them seeming just start this flushing/siphoning cycle on its own. I'm using a Fluval SP6 pump which is said to be microprocessor controlled and will throttle the pump flow based on the load. Every once in a while when I pour in a little frozen food and maybe 1oz of water right in from of the return, this will be triggered. I wonder if it's actually the changing of the pump flow rate change that triggers it?

I hear what you are saying about trying to push too much water through the Durso but the Durso and drain pipe is 1.5" ID PVC which is rated at 2100GPH at zero pressure. I'm using a Fluval SP6 for the return which is rated at 3434GPH at the head which drops to around 1400GPH at 10 feet which is where I'm at so don't think it's a too much water situation.

Are there any drawbacks to making the hole a bit larger? This seems to be the easiest thing to try (I'd rather not throttle back the flow rate).

[sirreal63]

In spite of what you may have read or been led to believe, you cannot safely push 2100 gph through a 1-1/2" open channel drain. As you can see 1400 (it's probably less with the resistance of fittings) is pushing it. There is no harm in trying to adjust the air hole, but don't be surprised of it doesn't fix it. If it doesn't work, put a gate valve on the return, it will not hurt the pump at all and will allow you to fine tune the drain.

[EllisJuan]

sirreal is right, making a bigger hole may not fix it. But, I bet it will. That is a really small air hole for the amount of water you are pushing through it. Enlarge the hole in small increments.

[mskvarenina]

The hole is quite small, looks like about 1/8" at the moment.

This FAQ seems to say it's caused by the drain extending too far into the sump.

http://www.dursostandpipes.com/frequ...go-up-and-down

In my case I'm guessing it both as the hole does seem very small and the pipe in the sump goes down about 8-10" into the waterline.

I think I'll try both mods, bigger hole and shorter pipe...

[ca1ore]

Regardless of whether that helps, you are still pushing way too much down a single pipe and are asking for a flood.

[SGT_York]

2100 GPH is a full pipe of water, it is not a partial air and water mix estimate.

Durso's get really (really) noisy when the reach more than 50% of their rated capacity. All that slurpage is when the water blocks off the air passage and tries to pull/push the remaining air down the tube. As the air tries to push up you get noise. Adding a larger hole will help slightly, cutting the outlet pipe to the sump water level will remove some of the backpressure causing the sluping siphon. The best way to fix the siphon/noise would be to reduce the flow so water only flows down the pipe sides and leave the center empty for air to freely travel.

If you want a good long term solution look into a herbie setup. It uses two or three drains. Is completely silent (no noise at all) and doesn't have any bubbles in the sump because the drain line has no air in it at all, it will easily push the 2100 GPH flow of your pipes without problem and you can let your return pump run at maximum efficiency.

[mskvarenina]

I'd love to convert my tank to a Herbie but the tank is pre-drilled and I cannot add another hole nor convert it to a hob overflow

And yes. It's very noisy

[drew2007]

U can do a herbie with what you have now. Use the larger of the 2 holes as your emergency drain and the other as your full siphon drain. Then just plumb over the top of your tank a return from your pump. Herbie is 2 holes and bean animal is 3.

[Azraz]

Go to the herbie, I played and changed and stressed and fiddled and the durso drove me nuts. Since converting to herbie, my tank is total silence and I could not be happier. Be a convert and you to will be happy!