Microbubbles everywhere

[wkopplin]

I have my new pump installed and I am getting microbubbles coming out of my returns. I never had them when the old pump was on there. Any ideas as to where they could be coming from? I checked all of the plumbing and could not find where it would be drawing in air.

I guess I will put some more pvc cement on the new joints and see if I can seal it up. Nothing has changed in the sump, so I doube it is coming from there. Has to be a leak that is drawing air.

[reefer]

it could be your pump impeller is cavitating inside the pump housing.

[NaCl_H2O]

Trapped air in your return plumbing? But that would quit after 30 min or so I would think!

No micro bubbles in the sump?

With the pressure you have, I think a poor PVC joint would be leaking, not sucking air?

[Ram_Puppy]

My first guess would be the same as reefers, cavitation.

[wkopplin]

How can I correct that? I checked for leaks and there were none. I also thought water would be leaking out and not air, but thought I would give it a chance. The sump has a dam of rocks before the intakes for the pumps. That is how it has always been and I have never had a bubble issue. How would I fix the cavitation issue?

[Tim Marvin]

If it was sucking air it would be before the intake of the pump. are all the fittings tight on the pump? This needs to be fixed quick, as some corals will not withstand constant air on them.

[Tim Marvin]

One other thing. Are the returns under water? Sometimes the return of the water into the tank will draw air down off the surface and mix it too look like micro bubbles from the pump. You will see a tiny line of air that looks like a twister coming down off the surface.

[wkopplin]

They are under water. I checked all of the fittings and they are tight. I used a good amount of teflon tape and screwed them down as far as they would go. I put some filter sponges on the intakes in the sump just in case there were bubbles there thinking maybe that would keep them out, but I am still getting sir. Is it possible that there is some air trapped in the pump and it is slowly working its way out? It has been 24 hours since I fired it up....

[NaCl_H2O]

I fought bubbles in mine once for weeks & couldn't figure out where they were coming from. Turned out they were coming from the skimmer and were in the sump all along, I just couldn't see them. I temporarily hooked up a bright light above the sump and I was amazed - bubbles! In dim lighting, it's impossible to see the microbubbles, but easy to see them under the lights in your tank!

I gotta think this is more likely than an "accidental venturi" in your plumbing ;)

[wkopplin]

Might be. I will explore that a little more. Only thing is that the sump is a 180 gallon tank with the skimmer on one end and the intakes on the other. Pretty long way for skimmer bubbles to travel.

Other wierd thing is that the returns going to the other tanks do not seem to have bubbles and they are all plumbed off the main return pump as well. Not sure. I raised the return nozzles so they are pointing towards the surface and that helped the bubble problem beacuse they are leaving the tank quicker.

[NaCl_H2O]

That's wierd :? Use the light to verify no bubbles in the others too??

You said you used flex PVC right? I'm not familiar with this stuff, but could it be contributing? Maybe if it is bent in too tight of a bending radius, cound it have a small crack that's giving you the venturi? Or maybe air trapped in the return plumbing - I have no idea how you would determine this, or fix it? What if you shut off the pump and let the siphon try to clear the return lines, but start it back up before the siphon breaks and give you more air in the return plumbing.

It is kinda fun sitting here trying to solve someone elses problem when I really don't have a clue :lol:

[wkopplin]

Hehe. I know. Try sitting in my shoes trying to solve this. I did shut the pump down and re-checked all of the connections. It might be the flex pvc, but I put so much pvc cement on the joint that I doubt any air could get through there.

I looked closely at my coral frag tank and there are bubbles going through the return there too, the water is just going so fast you cannot see them and they go to the surface pretty quick in there.

I will put a bright light on the sump and see if there are any bubbles getting to the intakes. This new pump draws more water than the old one so maybe it is somehow causing a stronger current in the sump and pulling the bubbles in.

[scuba_steveo]

Well Blake I am affraid that I do not have any good theories that have not been discussed yet. The only thing I can think is to get Dan to make you a bubble eliminator for your sump like mine. The thing works like a charm.

[reefer]

the cavitation could be caused by a number of issues. cavitation in the pump housing can destroy the impeller, btw. but if its the result of bubbles escaping the skimmer, there may be little yoou can do, except reduce the air being intaked into the becketts. one way you can check if its coming from the skimmer is to shut off the air intakes completely, and let it run in that state for a day or so. if the bubbles disapate in the tank, then you know the root cause of your problem. then your choices will be to either reduce the output of the pump, or reduce the air intake. just some ideas..... hth!
8)

[wkopplin]

Thanks! That is my next experiment.

[matt]

Hey, don't go blaming that skimmer! :-D

Seriously, you were using the skimmer before, soooo......