After research still having BioCube problems

Quick background...

I have been keeping reefs very successfully and ran a couple LPS back in the late 90's. Recently started keeping a reef again due to a gift of a 14g BioCube for Christmas. I would have my 90g up and running but we are still active duty military and tend to move every few years or so.

Anyway, this BioCube has been set up exactly 15 days. Everything is working just fine. Removed the bio balls, removed the drip tray and the bottom tray in chamber 2. The problem I am having is short bursts of micro bubbles and I can't figure out where they are coming from. I have the water level in the back all the way up to the return tube.

Here is a diagram of how it is set up. I know, it isn't exactly to scale 8)




What I have done today is jam filter floss around the powerhead and a roll of it at the bottom of chamber 2 in order to stop any bubbles from getting passed (the 'filter floss' is that blue and white media you can get at a LFS in bulk). It seems like about every 5 seconds I will get a quick blast of micro bubbles. If I had to approx how many bubbles I would say 10-20. Most are tiny but a few are larger. It doesn't sound like a lot but when the tank is sitting literally a foot from my desk chair that I sit in a lot during the day, it is ultra annoying.

After researching this online I can't find a solution. I haven't heard of a break-in period for a skimmer lasting more than a week but I could be wrong.

THANKS for any suggestions, comments, concerns or criticism. Judging by the diagram, where are these bubbles coming from?

 

Check your return intake for mini whirlpools. Happens in my sump when I dont keep track of evap.

 

The water line is about an inch above the tube to the return and although there is a decent amount of water movement, I didn't notice any whirlpools.

Thanks for the quick reply and I thought that was it when I read it.

 

Periodic bursts of bubble are typically caused by cavitation (either by a whirlpool) or a collection of bubbles from a skimmer that stay in the return pump until they hit "critical mass" and burp out all at once.

 

Agreed. But what I can't figure out is the source of the problem. I have checked again and there is no 'whirlpool' being sucked down into the return hole at the top, there can't be a whirlepool at the inlet to the powerhead do to it being so deep. If it is the skimmer, how are bubbles making it all the way through the onslaught of filter media and the stock barrier by the powerhead?

I have done my best to figure out the problem through process of elimination but as I type this a Firefish goby is trying to feed on air bubbles being shot out the return.

Thanks again for any and all comments.




*Please click on the attachment for a larger pic..

 

Hmmmm.

Maybe temporarily way overfill the sump so the tank is 100% full. Maybe there's a crack in the tube to the return and air is being sucked in via Venturi Effect. Do the microbubbles disappear?

Also, don't run the skimmer for a while. Do the microbubbles disappear?

Just trying to narrow down possibilities.

 

I will fill it up all the way and see what happens. The bubbles do disappear. The water is really clear (considering the amount of media I am currently running) and it is easy to follow a bubble back to the surface. Some of the bubbles are large enough that they shoot right to the surface.

I removed the skimmer, for a very short period, and the bubbles still appeared but that may be due to the fact there was still bubbles throughout the system that hadn't made it's way out of the tank.

If the problem is air entering the tank through a leak then the tank would be dripping. If it is a whirlpool effect wouldn't I be able to see it as it would be close to the surface? If the skimmer is the problem then how is air bubbles traveling down far enough to make it to the powerhead? Possibly there is air trapped through the many media and floss that I am using and it is slowly making it's way out?

It's weird to say the least. Thanks again for the replies everyone.

 

I could be traped it the medis but that seems very unlikely. if you remove d the skimmer and the bubbled stoped there could be a leak and yyou might not know it yet!!

ITS THE CURSE OF THE BIOCUB LOL

 

Satisfied 29g biocube owner for 2 years here: I agree with the divide and conquer idea. Remove all of the media bags, filters floss etc so you can look down in the sump chambers. Get a flashlight and watch at minimum configuration the water flow. Assuming you can strip things down to just the pump pulling water through a bare bones sump you will either not have the problem or you will be able to see the problem. We have a definite maybe. :-/ Gut feeling tells me something is "burping".
Pretty sure we are not dealing with a crack or a curse.