Microbubbles.......Uuuuuugh!

[steveoutlaw]

I just got my new setup together and I'm getting micro-bubbles in the tank. I have an Eheim 1260 that Tees off to the 2 returns. The only thing I can think of that is causing it is this; They drilled 4 1" holes instead of 2 1" for the drains and 2 3/4" for the returns. I have the 1" bulkhead reduced to 3/4 both before and after (3/4" out of the pump, goes through the 3/4" Tee, increases from 3/4 to 1" on the underside of the bulkhead, reduced from 1" to 3/4" on the topside of the bulkhead, and 3/4 lockline into the tank. Could it be the increase/reduce at the bulkhead that is causing the microbubbles? What can I do to stop them?

[steveoutlaw]

Anybody???

[Origami]

I just got my new setup together and I'm getting micro-bubbles in the tank. I have an Eheim 1260 that Tees off to the 2 returns. The only thing I can think of that is causing it is this; They drilled 4 1" holes instead of 2 1" for the drains and 2 3/4" for the returns. I have the 1" bulkhead reduced to 3/4 both before and after (3/4" out of the pump, goes through the 3/4" Tee, increases from 3/4 to 1" on the underside of the bulkhead, reduced from 1" to 3/4" on the topside of the bulkhead, and 3/4 lockline into the tank. Could it be the increase/reduce at the bulkhead that is causing the microbubbles? What can I do to stop them?

 

Have you checked for an air leak at one of the plumbing joints, Steve?

[DaveS]

I used to get micro bubbles from my return. It was T-ed and the bubbles always came from one side so I just figured it was due to an air leak somewhere on that side. After looking around forever I couldn't find it.

 

On the intake to my return pump, I have a foam filter surrounding the strainer. Turns out the filter was getting full of muck and that restricted the intake to my pump. The microbubles where from cavitation of the pump impeller! Once I took the filter off and cleaned it real good, the bubbles were gone. Don't know why they like to come out of one side only but now when I see microbubbles I know it's time to rinse the foam.

 

Check your intake to make sure it's not getting restricted too much. Your pump needs the right amount of intake flow or it may get unhappy.

[steveoutlaw]

Have you checked for an air leak at one of the plumbing joints, Steve?

 

I'm not seeing any water leaking from any of the joints so I'm assuming there is no air getting in.

 

Check your intake to make sure it's not getting restricted too much. Your pump needs the right amount of intake flow or it may get unhappy.

 

There is some macro algea that is clinging to the intake. I will remove it and see if I notice a difference. Thanks.

[mogurnda]

I'm not seeing any water leaking from any of the joints so I'm assuming there is no air getting in.

A leak upstream will be under negative pressure. Air will go in, water won't come out.

[Origami]

A leak upstream will be under negative pressure. Air will go in, water won't come out.

Exactly.

[steveoutlaw]

I think the only area it could be coming from is going from 3/4" to 1" and then back to 3/4" in the bulkhead (a span of about two inches). Would it be better for me to let it increase to 1" at the bulkhead and keep it at 1" for the 23" it takes to get to the top of the overflow and then reduce to the 3/4" locline? Or would this still be an issue?

[Origami]

It may not be there, Steve, but look for the air leak on the drain side (going into the pump), not the return side (which I believe you said was 3/4"). If it's an air leak, it would be there. Could you be getting a leak at the intake of the 1260?

[steveoutlaw]

It may not be there, Steve, but look for the air leak on the drain side (going into the pump), not the return side (which I believe you said was 3/4"). If it's an air leak, it would be there. Could you be getting a leak at the intake of the 1260?

 

 

It wouldn't be on the drain side. I've looked in the return chamber of the sump and found that there are no microbubbles. I'm just going to have to re-do the plumbing and see if that is part of the problem.

[Jon Lazar]

If the pump's intake is restricted too much, it will cause low pressure between the intake and the pump. When the low pressure water hits the impeller, microbubbles will form. You don't need a leak for this to happen.

[steveoutlaw]

If the pump's intake is restricted too much, it will cause low pressure between the intake and the pump. When the low pressure water hits the impeller, microbubbles will form. You don't need a leak for this to happen.

 

 

Jon-

The pump is brand new and there is nothing restricting the intake. This is driving me crazy!!

[dschflier]

What are you planning to do with the re-plumbing?

[YBeNormal]

You can have a loose seal or joint on the return side that will cause micro bubbles without causing a leak. It took weeks for me to figure that out on my tank.

[steveoutlaw]

What are you planning to do with the re-plumbing?

 

I'm thinking about just using washer hose and barbed fittings instead of hard plumbing it. I think this would prevent what bob is talking about with a joint not being completely sealed. Got any ideas?

[traveller7]

I'm thinking about just using washer hose and barbed fittings instead of hard plumbing it. I think this would prevent what bob is talking about with a joint not being completely sealed. Got any ideas?

If the pump is powerful enough, as Jon posted, the input side head is enougth to cause a condition where the impeller actually cavitates creating micro bubbles. This can occur in cases of small intake line diameter, long intake lines, intake lines requiring the pump to over come gravity.

 

Output lines can, but rarely in our applications contribute to cavitation, but they can produce the venturi effect.

 

In general: Always oversize the pump intake line, regardless of the intake fitting. Definitely make sure the intake line is larger then the output. At some point, most of our applications don't care once we hit 2" diameter pipe.

 

fwiw:

http://www.reeflopumps.com/images/tips.pdf

[DaveS]

I'm thinking about just using washer hose and barbed fittings instead of hard plumbing it. I think this would prevent what bob is talking about with a joint not being completely sealed. Got any ideas?

 

I still think it's cavitation from a restricted input like I mentioned in post 4. If you are going to replumb anyways, I would suggest that you experiment a tiny bit while you are at it.

 

Replumb one side of the pump at a time and run the pump in between. If you are going to go barbs and hose, it will be very easy to do. I'd start with the output first because I think it's cavitation and you can prove it that way. Regardless of the side, if you only do one and still see the bubbles, you will know for sure which side it is coming from. Then your problem is cut in half.

 

The only thing worse than making a mistake is not learning from it...

Edited October 22, 2008 by DaveS

[steveoutlaw]

The pump is an eheim 1260 and it is being used submersed, so I don't think it's a problem with a restricted intake. The pump goes to a barbed T and then to each of the return bulkheads. I'll try plumbing it just to one side and then the other......that should tell me if it's the T (home made) or something else.

 

Thanks for the help.

[dschflier]

Did you ever figure this out. I just replumed my whole setup and I am now getting micro bubbles as well. I havn't had a lot of time to try and igure the issue out. I switched from a Iwaki100 to a hammerhead pump.