My overflow drain has gas

outtafocus · #1 09-02-2005, 01:19 AM

I have found the water in my overflow constantly rises and falls. It goes up an inch higher than I want it, then drops and causes that horrible sucking sound. I am using the hoffer gurgle buster style plumbing.
The water then falls straight down into my sump, but as the above described "flushing" happens the water surges and burps out a large amount of air into the sump, causing splashing and sloshing.

I have read that because my plumbing drops straight down, it causes back pressure in the pipe. Which in turn causes the rising and falling and the burping.
What is the best solution to this issue? I was looking at changing the staight 1"pvc to the flexable style and running it at an angle into the sump. Will this even help?
What are your thoughts and ideas?
Thanks

vanreefer · #2 09-02-2005, 01:47 AM

I had the same problem.... I still used 1" PVC but put a 30 degree elbow in it... solved the problem once I made the Gurggle buster as well

HTH

Dan

Delphinus · #3 09-02-2005, 07:41 PM

I've had similar issues when I had my overflow go straight down. Not sure if it's a complete solution but having a bend or something along the lines of a 45 so that the water can "slide" into the sump seems to lend itself better to a steady-state operation. There could also be maybe not enough air coming into the overflow. Anyhow just some random thoughts I hope might be helpful, good luck.

outtafocus · #4 09-02-2005, 09:14 PM

I will try adding a 45 elbow right below my tank, as it passes into the stand. I will let you know if it worked.
Its kinda funny, my original plan had the 45 in my drain, but after several suggestions, I went with the straight down idea.

Johnny Reefer · #5 09-02-2005, 09:18 PM

I'm planning on getting my tank drilled for a side overflow in Oct. or Nov.
Looking forward to hearing about your results!

Cheers,

outtafocus · #6 09-03-2005, 04:46 AM

Adding the 45 helped reduce some of the sloshing and burping, but because it is also adding more back pressure, I feel I am getting more fluctuation in the water in my overflow chamber. Bigger water rise, more pronounced flushing.

I have come to a conclusion that I may have been trying to force too much water through my overflow. When I added the new Rio 20HF pump is when I started to noticed the flushing. I used my ball valve to throttle down my pump and it seems to have reduced but not elliminated the flushing effect. My overflow plumbing has no problem handling the amount of water I am putting through it, but with more water comes more air being sucked in to the system.
I was looking to get away with no powerheads in the tank and relying on the return pump through a SCWD for my only circulation. I think I am going to return the pump and use powerheads for movement.
Now I just need to decide if the Mag7 I own will be sufficient. When I was doing my initial water tests with the Mag7,I had no flushing issues or sloshing. I believe even a Mag9.5 may be to much flow.
Big Als said I could return the pump if I didnt like it.

BT05 · #7 09-03-2005, 07:07 PM

I only get this problem whenever there is not enough air entering my standpipe or there is a dramatic change in air pressure inside my canopy. Usually when I whip the door open is causes a flush, then settles down shortly after. Doesn't happen if I open the door properly though.

I have a so called "stockman standpipe" which is just the "hofer" with the coupling reversed. So try your standpipe out in the stockman form, it's more sensitive but the amount of air drawn in can be controlled easily. With the Hofer, air is drawn from the drainage holes in addition to the hole in the end cap. Unless the holes are aligned properly, one will always be drawing too much/too little air causing the flushing effect. The stockman doesn't have this problem since the holes are always submerged and enclosed by the coupling.

Then again, this might not apply as my drainage plumbing doesn't drop straight down into my sump but it's worth a shot.

outtafocus · #8 09-06-2005, 10:52 PM

By replacing the Rio pump with the less GPH mag7, I feel I have reduced the burping to the point of it being undetectable and the piping entering the sump is at a 45 degree angle. I have also inverted the intake bell on my hoffer gurgle buster and I now have a Stockhoffer gurgle buster standpipe. This have removed all signs of sucking air noise and slurpping.
However the water inside my overflow tower still continues to rise and fall 1 inch. I know this sounds insignificant but it could potentially cause an issue for my auto top off system (Tunze Osmolator) as this rise and fall is felt by my sump.
I have been running a test for the past hour to see what effect this fluctuation has on the Osmolator. So far it seems to be unaffected. I am worried that as soon as I leave it alone for even the shortest amount of time it will want to malfunction.

What is you opinion on this matter?
What do you feel I can do to further reduce the rise and falling?
(the 45 on the drain plumbing is as close to the tank as I could get it, as follows- bulkhead-3" of straight pvc-union-45-8"angled pvc into sump)

outtafocus · #9 09-06-2005, 11:04 PM

low water level

high water level

Delphinus · #10 09-06-2005, 11:27 PM

Basically it's still burping then. You should be able to adjust it, one way or the other, into a steady state. I mean, I don't even see the levels in my overflow chambers varying by 1mm, they're that steady. (I don't have any overflows that go straight down though, all of them have a bend of some sort along the way).

In your case I'm wondering if there is some kind of air flow issue within the overflow pipe. How much air can get in there now? You may need to increase the air intake's ability (drill more holes, or enlarge the hole that's there).