Micro Bubble Help

[Steelhead1]

I have an overflow rated for a 75 gallon tank and a Cap 220 return pump. I have been running flexable hose for my return (untill this weekend). My skimmer sits in my sump. My return pump is located in the last chamber of the sump. The water from the return and skimmer has to go thru the chaeto and three baffles before it hits the return again. I have even put a sponge over the last baffle to kill any potential bubbles. I can not see any bubbles in the chamber that holds the return pump. I thought maybe I had a leak in the flexi hose so I decided this weekend to plumb the return with hard pvc. everything turned out great. I was very diligent when I made each connection. plenty of cement. Zero Leakage.
I still have micro bubbles. Not huge amounts, but enough that I can see them consistantly. I cleaned the return pump about a week ago. I didnt see anything that could cause bubbles inside the pump. The impeller blades looked ok to me. This pump is at least 3 to 4 years old. The id of the pvc is 1/2in the id of the flex hose was 3/4in. I thought potentially by restricting the flow this would make a differance; it didnt.
Can you guys help me out. What the heck am I overlooking??

 

[Tang420]

If you can raise the water level in your sump and see if that helps. How long have you had this issue in that tank?

 

[Aquarist007]

what is the actual flow rate through the sump area?

 

[Tang420]

If you can raise the water level in your sump and see if that helps. How long have you had this issue in that tank? If this is a new issue in a tank that you'v had setup for a while look at anything you have added or changed since you noticed the problem. I would try to raise the water level in the sump first...

 

[watergator]

Interesting! I have the same problem, and I'm unable to find any air leaks. I even re-piped my system twice with pvc. I think the pump may spin so fast that it creates the air bubbles inside the volute of the pump...

 

[Aquarist007]

<a href=showthread.php?s=&postid=12344835#post12344835 target=_blank>Originally posted</a> by bonnethead
Interesting! I have the same problem, and I'm unable to find any air leaks. I even re-piped my system twice with pvc. I think the pump may spin so fast that it creates the air bubbles inside the volute of the pump...

that is why it would be helpful to know your flow rate through the sump and the gph of your pump

 

[watergator]

Not sure of the flow in mine. I have a 2" overflow and a 1" in-tank drain. But my sump is always full and the pump doesn't out-run the water.

 

[Steelhead1]

I have been running the water level as high as I can in the last chamber. It doesnt seem to change the issue.
I have added a koralin 3 power head and a hydor rotator unit. These are both on the opposite end of where the bubbles are coming from.
I have no idea of the exact flow rate through the sump area. Would you by chance know where I could go to figure it out??
If the flow is too fast going through the sump could it carry the bubbles from the skimmer to the return? I do not believe this is the case though. I can not see any bubbles in the return chamber at all. I have looked very carefully.

 

[nmbeg]

My had a similar problem.... my issue was too much flow through the sump.... the drain into the sump had so much flow it was turbulent and made lots of bubbles in the sump and in the display. filter sock fixed it.... although i hate filter socks.

but your problem seems different with no bubbles in the sump.

 

[briangg57]

Do you have any bad algea causing nitrogen bubbles lik I had?