Question about U-tube overflows

[lanman]

The 'bubble' of air in my U-tube overflow seems to have gotten larger over time. Perhaps from little bubbles of air in the water?? Do they eventually just get so much air in them that they lose suction? Should I re-set it once in a while to keep that from happening?? Have I just been lucky?

 

bob

[YBeNormal]

Do they eventually just get so much air in them that they lose suction?

Yes, that can and does happen.

 

Should I re-set it once in a while to keep that from happening??

Yes, that would be a good idea. You might also chase down any sources of microbubbles and try to clear them up. Increasing the flow rate through the u-tubes will also help keep them clear of trapped air bubbles.

 

Have I just been lucky?

Maybe. Let's hope your luck continues to hold out.

[extreme_tooth_decay]

Back in the day I had a U-Tube type overflow that had a built in nipple at the top

designed to attach a small air/water pump (Aqua Lifter) that constantly pumped it out

 

It was pretty cool

 

 

tim

[Caribbean Jake]

Bob-YBenormal hit every point, I just want to add, that sometimes the bubble on the U tube is due to low pressure flow, or mis-alignment of the ini-the-tank collection box. You can start by leveling the in-the-tank box to minimize or eliminate the bubbles, and if that does not work, then I suggest either lowering the box or getting a more powerful return pump so your pressure flow increases. just my 2

[lanman]

Bob-YBenormal hit every point, I just want to add, that sometimes the bubble on the U tube is due to low pressure flow, or mis-alignment of the ini-the-tank collection box. You can start by leveling the in-the-tank box to minimize or eliminate the bubbles, and if that does not work, then I suggest either lowering the box or getting a more powerful return pump so your pressure flow increases. just my 2

[YBeNormal]

Insert an air hose with the end of the hose at the top of the u-tube. Submerge the ends of the u-tube and suck the air out. There will still be a small bubble or two in the u-tube. Start your return pump and wait for the full water flow to begin, then pump the u-tube up 'n down rapidly. The air bubble will break into smaller ones that will be swept out of the u-tube, assuming you have sufficient flow.

[lanman]

Insert an air hose with the end of the hose at the top of the u-tube. Submerge the ends of the u-tube and suck the air out. There will still be a small bubble or two in the u-tube. Start your return pump and wait for the full water flow to begin, then pump the u-tube up 'n down rapidly. The air bubble will break into smaller ones that will be swept out of the u-tube, assuming you have sufficient flow.

 

Woohoo!

 

Elfing brilliant!

 

Works when it's still running, but you want to reduce the size of the bubble, too! I couldn't QUITE get the bubbles to break up small enough to flow out of the tube - so there is a little bubble in there. But I'm sure it's good for another month!

 

Got my first yummy taste of tankwasser, too. Nothing a swig of Scope and a cup of coffee couldn't take care of.

 

I just KNEW there had to be a better way.

 

Many thanks!

 

bob

[YBeNormal]

If bouncing the u-tube up and down quickly (bumping it on the overflow in the process) does not get all of the bubbles out, then you definitely don't have enough flow to keep them clear under normal operation. This greatly increases the chances of the siphon failing (while you are away of course). Make sure there is enough extra room in your tank to hold all of the water in the return chamber of your sump.

 

If you are interested in an even easier way to do this and are willing to DIY a little, drill a small hole and add an airline check valve to the top of the u-tube. You can then connect a short piece of airline tubing to the check valve and suck the air out that way. The advantage of this setup is that you can suck all of the air out without taste-testing the tank water.

[lanman]

If bouncing the u-tube up and down quickly (bumping it on the overflow in the process) does not get all of the bubbles out, then you definitely don't have enough flow to keep them clear under normal operation. This greatly increases the chances of the siphon failing (while you are away of course). Make sure there is enough extra room in your tank to hold all of the water in the return chamber of your sump.

 

If you are interested in an even easier way to do this and are willing to DIY a little, drill a small hole and add an airline check valve to the top of the u-tube. You can then connect a short piece of airline tubing to the check valve and suck the air out that way. The advantage of this setup is that you can suck all of the air out without taste-testing the tank water.

 

Lack of flow - I think you're right... I hadn't really paid much attention, but I think my pump needs to have the vent holes cleaned. I put my hand in front of the input to the tank, and it isn't what it used to be. So I took a look, and there are a few dead spiders and stuff stuck to the vent holes - probably slowing down the flow. Will pull it tomorrow afternoon and clean it up.

 

Thanks again!

bob

[quazi]

I have had a u-tube overflow on my tank for 17 years and I have never had a problem with it, other than it filling with aglae. So, it must be reemed out every 3 weeks to a month. The key is water flow. Any bubbles that are left when I suck the air out with the airline hose are quickly eliminated due to the volume of water going through the tubes. Adjust your overflow properly and you will not have a problem.

[Almon]

Yes, I agree, increased flow is the best solution. I use 1 pump and 4 overflows for my 3 tanks and never ever have bubbles collect.

[lanman]

Yes, I agree, increased flow is the best solution. I use 1 pump and 4 overflows for my 3 tanks and never ever have bubbles collect.

 

What would be the correct pump for a 45-gallon or a 58-gallon tank? I think the 'suggested' SEN 500G might not be enough; I looked at the statistics and it loses capacity really quickly with head increase.

 

bob

[rooroo]

Well for the overflow you want to get as close to 600 GPH as possible. That is also appropriate flow going through the sump for a 58. I think I have a Mag 7 on my tank that does around 500 GPH. That would probably work great.

 

A tip to keep algae out of your U-Tubes - Put a little aluminum foil over the overflow and U tube. You can mold it to fit just right and it'll block most of the light so you may get small buildup but nothing that would ever require cleaning. I used to do this with my overflows and I never had to clean the U Tubes.

[lanman]

Well for the overflow you want to get as close to 600 GPH as possible. That is also appropriate flow going through the sump for a 58. I think I have a Mag 7 on my tank that does around 500 GPH. That would probably work great.

 

A tip to keep algae out of your U-Tubes - Put a little aluminum foil over the overflow and U tube. You can mold it to fit just right and it'll block most of the light so you may get small buildup but nothing that would ever require cleaning. I used to do this with my overflows and I never had to clean the U Tubes.

 

I already have a dishtowel covering mine - because of how nicely it cuts the noise down. I ordered a Danner Mag-7 yesterday. I am starting to clear the area for the 58-gallon tank today. Soon, we will have this great discussion about how to switch everything from the 45 to the 58

 

bob