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Air in the drain line cause large bubbles in sump


sheac12

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Hi all. I am back again with more questions. I am having a problem with large amounts of air in my drain from the tank. My tank is a AGA with a Mega Flow Overflow kit connected to the sump using flexible PVC. I have the overflow depth set to the suggested 1 inch from the top. I am using the 1" drain and the .75" return.

 

I am trying to figure out where the air is getting into the drain line. I dont know if it is in the elbow in the overflow or if the flexible PVC connection is not tight.

 

I have a video of the problem that I am going to post later today, but I am hoping someone else has run into this issue before.

 

I think that the problem is the crappy connection the two pieces of the elbow make, but I dont know that for sure.

 

Anyone else run into this before?

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Hi all. I am back again with more questions. I am having a problem with large amounts of air in my drain from the tank. My tank is a AGA with a Mega Flow Overflow kit connected to the sump using flexible PVC. I have the overflow depth set to the suggested 1 inch from the top. I am using the 1" drain and the .75" return.

 

I am trying to figure out where the air is getting into the drain line. I dont know if it is in the elbow in the overflow or if the flexible PVC connection is not tight.

 

I have a video of the problem that I am going to post later today, but I am hoping someone else has run into this issue before.

 

I think that the problem is the crappy connection the two pieces of the elbow make, but I dont know that for sure.

 

Anyone else run into this before?

 

the dorso pipe should have a air port open on the top, make sure thats not obstructed, the key is to let the air escape before it has the chance to flow downward towards the sump...

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the dorso pipe should have a air port open on the top, make sure thats not obstructed, the key is to let the air escape before it has the chance to flow downward towards the sump...

 

As far as I can tell it is clear. I uploaded a video showing the sump and the overflow. Hopefully that may help.

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I love that video.

I think that everybody has had to tackle this issue with their tanks, and you'll get a number of testimonials on how to fix it.

 

Here's mine:

 

IMGP8001.jpg

 

No crazy plumbing t's and air ports and whatnot - and no bubbles with an eheim 1260 wide open, pictured below in a very old picture. I copied what Sean has behind the scenes at F&F.

 

IMGP8101.jpg

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bigJPDC

 

Glad you enjoyed the vid.

 

In the first photo is that your bulk head? How did you get the pvc to stay sealed to the barbed end of the bulk head, lots of glue?

 

Thanks

Edited by sheac12
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bigJPDC

 

Glad you enjoyed the vid.

 

In the first photo is that your bulk head? How did you get the pvc to stay sealed to the barbed end of the bulk head, lots of glue?

 

Thanks

 

:eek: No glue man - the PVC all terminates to a hose barb that matches the hosebarb connection on your megaflow bulkhead fitting Then use stainless steel hose clamps to clamp down on a short piece of that braiding tubing you are using to connect them. I can take more pictures tonight - let me know.

 

jp

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As far as I can tell it is clear. I uploaded a video showing the sump and the overflow. Hopefully that may help.

 

 

In the video I see you have no clamps where the tubing connects to the barbed connections off the bulk heads. Get clamps on both of those!!

 

First, even the slightest gap will suck air in and can be your source. Second, if one of those tubes came off you will have a big big mess. Clamp them as a precaution.

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Ok, what kind of clamps? Are we talking about zip ties, or those metal ones with the screw?

Either way I will throw some clamps on there tomorrow after work and see if that fixes the problem.

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IMO the air is entering your drain as it should, through the air hole in the top of the durso. If you completely plugged this hole, you would have no air mixing with your water as it went down the drain -- but you would have a complete siphon. The siphon would draw the water in your overflow down to the strainer, when you would hear a sucking sound, and then it would rise until the siphon started again, and repeat that process over and over again. Not pleasant. The air hole helps maintain a steady rate of flow down the drain lines. You can actually adjust the rate of flow by adjusting the size of this hole.

 

So, I don't think your problem is the fact that you have air in the drain lines, just that it is causing large bubble in the sump. This is a simple fix. Basically you want to position the drain so that it enters the water in your sump at an angle, with a portion of the tube above the water line. This allows the air to escape before it gets down into the water and causes bubbling. There are many ways to do this, my favorite (using PVC) is to use a 45 to get then angle, and then a T entering the water, with the T part sticking up to let the air out.

Edited by Rascal
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In the video I see you have no clamps where the tubing connects to the barbed connections off the bulk heads. Get clamps on both of those!!

 

First, even the slightest gap will suck air in and can be your source. Second, if one of those tubes came off you will have a big big mess. Clamp them as a precaution.

 

Agree with that.

 

Also it looks like you can (and should) push the tubing a lot further onto the barbs (carefully)

 

tim

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Agree with that.

 

Also it looks like you can (and should) push the tubing a lot further onto the barbs (carefully)

 

tim

 

I went ahead and fixed my setup as suggested. I added clamps to all my connections, I used the stainless steel ones. I replumbed with what Rascal suggested and the bubble problem isnt much better. The only thing is I didn't seal the pvc connections with cement so, I am going to do that and try again.

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probably not - the downside of trying to use air vents is that the rushing water can actually suck more air back in and through your plumbing. I even had one setup where I used a '+' shaped connector for double air venting and my sump looked like a hottub.

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probably not - the downside of trying to use air vents is that the rushing water can actually suck more air back in and through your plumbing. I even had one setup where I used a '+' shaped connector for double air venting and my sump looked like a hottub.

 

Yeah I am going to pick up a end cap put that on and see how it is behaving.

 

Also there are a lot of bubbles that come out of the end of the pipe that sticks up, when I get back from class tonight I will post another vid.

Edited by sheac12
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If the "T" is at the surface but the pipe extends farther into the water so that the end of it is fully submerged, this won't fix the problem. The opening of the pipe/tube at the end of the plumbing needs to be partially out of the water and at a 45 deg angle at least.

 

Try it this way: Manually lift the pipe/tube up until the water is literally pouring from it into your sump, at an angle. No more bubbles, right? But now it is too noisy and you've got a splashing issue to deal with. So lower it until the noise is reduced and the splashing goes away. IME this will happen when the end of the pipe is only about 1/2 submerged in the water.

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If the "T" is at the surface but the pipe extends farther into the water so that the end of it is fully submerged, this won't fix the problem. The opening of the pipe/tube at the end of the plumbing needs to be partially out of the water and at a 45 deg angle at least.

 

Try it this way: Manually lift the pipe/tube up until the water is literally pouring from it into your sump, at an angle. No more bubbles, right? But now it is too noisy and you've got a splashing issue to deal with. So lower it until the noise is reduced and the splashing goes away. IME this will happen when the end of the pipe is only about 1/2 submerged in the water.

 

woops!

 

My drain now goes like this(photo later) flexable PVC to 45 degree angle to 10 inch drop to 45 degree to tee to 6 inch drop.

 

Ok, that explains a lot. I have the tee about 4 inches above the water line and then a 6 inch tube that drops below the water line. Guess I shouldn't have glued all the pvc...oh well just go buy more.

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