Overflow evaporation?

[edolan]

I have setup a herbie overflow in my new build and have it running just as a test for the last couple of days. I have noticed that when I first dial it in it is dead quiet but after 6 to 8 hours I will start hearing noise from water splashing over the weirs and then I will hear noise in the siphon line. I looked in the overflow box and it looks to me like there are bubbles getting sucked in the siphon line that are being formed as the water splashes over the weirs as the water level lowers in the overflow.

I have been playing around with this and have noticed as I added about half a gallon of water to the sump it raised the water level in the overflow and would start running down the emergency standpipe. I then have to readjust the gate valve. I tried this again after the water level dropped after I had it set. This time I added a cup at a time to the sump which raised the return area and again after a couple of minutes the overflow raised to normal height

This seems to go against my understanding of evaporation only affecting the return area of the sump and all other areas staying constant. Has anyone else experienced this?

Is there possibly something else going on that I haven't considered?

 

[A sea K]

If you are raising the water level in the same area of the sump that the herbie is draining into then you're lessening the distance the water has to fall effectively reducing the suction the siphon is creating which will cause the water to rise in the overflow box. I've set up two different herbie type systems now, the first worked as expected right from the get go, the second seemed to need some to break in before it become consistent, until then it needed constant adjusting. They both used the same size plumbing but the second system was much taller than the first. One thing you can try is to raise the emergency pipe so the water doesnt "drop" over the weir creating noise, that way the only thing left to make noise is if level within the overflow gets too high thus draining into the emergency.

 

[edolan]

Thanks. Yes I did raise the emergency standpipe which helped prevent some trickle noise through weir and bubbles being caught in siphon drain. Also lowered siphon a bit thinking that might help a little.

The fluctuation I am getting in overflow is not evaporation like I thought at first. Tank ran all day completely quiet. Checking throughout day I noticed the level start to rise again even as level in return area has lowered from evaporation.

Now my thought is maybe it has to do with water temperature. Since I am test running the system I do not have a heater set up. At night as the temp lowers the water contracts and the level in overflow goes down?
Then the opposite during the day?

Is this possible? Any thoughts?

 

[A sea K]

I have setup a herbie overflow in my new build and have it running just as a test for the last couple of days.

I have been playing around with this and have noticed as I added about half a gallon of water to the sump it raised the water level in the overflow and would start running down the emergency standpipe. I then have to readjust the gate valve. I tried this again after the water level dropped after I had it set. This time I added a cup at a time to the sump which raised the return area and again after a couple of minutes the overflow raised to normal height

I think you need to just give it a little time to settle down. It can take a few weeks before the plumbing develops a slime coat and once that happens I would hope it will settle down. Just to be sure, the sump area the herbie drains into has a consistent water level?

 

[d0ughb0y]

I noticed the same. The overflow box water level goes down if the return section water goes down. If you keep return section water level constant using ato, then overflow box level will stay the same.

If return water level goes down, the pump water flow rate goes down. Just a little decrease in flow rate can cause enough drop in water level in overflow box. Just as turning the siphoned drain valve a little is enough to cause overflow water level to change.

 

[edolan]

Thx doughboy. I am just testing right now but will definitely set up my ato when I make the switch to my new tank. I wonder if running saltwater will make a difference as well and a steady temp when I put my heater in. I am sure what A sea K has said applies as well. Letting the tank break in and a slime coat forming to get a smoother flow. I imagine most people don't run it with tap water like I am. Just wanted to try everyting out before I do my final setup.

 

[homer1475]

Keep in mind also a herbie setup is finicky. I have to adjust mine about every other day. It's only a very small fraction of a turn on the gate valve, but still have to adjust it. I run filter socks and as they start to plug up I have to open the valve a bit, new sock close it down a bit.

I typically run my herbie so either the emergency has a slight trickle, or the water level just below the emergency otherwise I'm constantly fiddling with it. After a while you'll find the sweet spot where you don't have to fuss with it daily, this is why the bean animal is superior to the herbie setup.

Bean is set and forget, herbie is mess with it every couple days.

 

[A sea K]

I dont run socks full time and havent noticed whether or not they create any fluctuations in my herbie system but my system might need adjusting within a week or two typically.

 

[edolan]

So what if you go on vacation? I assume it can't go so far out of whack to be to much of a problem. Just run a little louder?

 

[ca1ore]

As noted above, maintaining precision with a full siphon is tricky. It will be affected by all sorts of things, including as you have seen, small variations in sump water levels. One thing you can do (I've done this) is to have the siphon output into a constant level section of the sump. At the end of the day, the only 'problem you'll encounter is noise.

 

[edolan]

Thx ca1ore. Yes the drains enter into the first section of my sump which has an overflow baffle and the level stays constant. One thing I am considering is adding a 45 to my emergency standpipe so that on the high swing of the water fluctuation in my overflow I don't get the loud dropping of water down the stand pipe. Not sure this will help or not though.

It just seems to me there is some variable here I am missing. Some systems seem to be more stable than others using this method.

 

[A sea K]

Thx ca1ore. Yes the drains enter into the first section of my sump which has an overflow baffle and the level stays constant. One thing I am considering is adding a 45 to my emergency standpipe so that on the high swing of the water fluctuation in my overflow I don't get the loud dropping of water down the stand pipe. Not sure this will help or not though.

It just seems to me there is some variable here I am missing. Some systems seem to be more stable than others using this method.

Not likely to help. I had two 45 el on the emergency overflow of my last system and it still made plenty of noise when water would flow down the pipe, if anything I think it made more. My current system is straight down and has a lot farther to fall but it seems it is about the same level and possibly quieter than what I recall.

 

[edolan]

I will skip the 45s then. I guess I will learn to live with it. Just hope it settles down a bit as it breaks in.
Thanks for your help

 

[LobsterOfJustice]

Make sure there is no air in your siphon line, and no way for air to get in. I'm learning my way through my first herbie setup and I noticed if air gets in this line the flow rate becomes inconsistent. If I turn the system off, when I turn it back on I have to close the ball valve near the sump to let the line fill, and let all the air bubble out the top.


Sent from my iPhone using Tapatalk

 

[edolan]

Ok just an update and maybe it will help someone else. I have gotten the herbie to be stable and silent and has been running for a week now without having to adjust it. What I found worked was to slow down the return pump.

I have a dc pump and had it at 40% and if I calculated head height correctly I was only running about 500 gph before I lowered it. I tried everything even turning it up at first but it wasn't until I slowed it down that it became easier to tune. I only dropped it to 38% but it has made all the difference. Maybe my pump is not as stable at higher flows or there is too much turbulence at the higher flow rate for the my siphon line.

Before I set up my herbie I had not read anything about controlling the return pump output to help silence it. The only thing I read was to set the flow I wanted and tune it with the gate valve on the siphon line. Having a dc pump makes it easier to control the pump but I suppose a ball or gate valve on the return line can help with this if you have an ac pump.

The only time it got a little loud was when I topped it off by hand not having my ato set up yet and put in too much water in the return area at once which threw off the overflow a little but I decided to leave it alone and it corrected itself after a couple of hours and is silent again. I still don't understand why but it seems a slight rise in the water level in the return area of my sump increases the water level in the overflow.

I imagine every tank and set up is a little different but I hope this helps someone.

 

[homer1475]

I also wonder if your full siphon line isn't below the weir enough so water falling over the weir teeth is causing it to suck bubbles? The top of your full siphon should be a minimum of 6 inches below the top of your emergency.

The idea is to tune the full siphon line to match the output of your pump using a gate valve. I suppose with today's DC pumps that can be turned up or down, would work instead of a gate on the full siphon.

 

[JMorris271]

The lower you set your full siphon, the more capacity in the sump you will need in the event of a shut down. I find 6 inches below the bottom of the water level at the spillway is a good medium. So that is sort of a herbie with no adjustments necessary.
I use one full siphon and an emergency. The return is over the back. Only sound I hear is the skimmer and powerheads.