Insane Micro-Bubbles

[Tehrab]

So, got my 75g up and running this weekend and holy jebus, micro-bubbles so bad that the drain compartment of my sump literally sounds like a jacuzzi not to mention the spray off of the bubbles make the evaporation rate absurd.

My overflow is a Megaflow so it has the 1" durso drain with a 3/4" return. I am pushing the return with an Eheim 1262 (At a 46" head, I am estimating 650/gph). The sump isn't struggling to maintain equilibrium as the levels stay constant. My return pipe is a 1" that is T'ed out and closed w/ball valve (For future fuge expansion) and then gets reduced to a 3/4" about 2" short of the return bulkhead. My drain line starts at the bulkhead as a 1-1/4" piece of spaflex (So it would fit the bulkhead barbs) and then gets reduced down to a 1" and does a nice, smooth curve down where it gets re-expanded out to a 1-1/4" at the water line and meets a T (This method, stolen from Sandman, did much to solve the noise issue).

All of that said, what would be the best course of action to eliminate the bubbles? From searching and reading, I have come up with the following:

• Silicone all fitting points
• Plumb a line back to the sump to reduce flow to the return head
• Buy a smaller pump, like the Eheim 1260

Is there anything else I could add to the list of things to try?

 

[rustybucket145]

Does your sump have baffles (bubble traps)? Do you happen to have a pic or diagram of how it's setup so we can look at it and help you trace down the problem?

 

[rustybucket145]

Also, I should note that I'm pushing over 1k gph through my 30gal sump without a single microbubble. So I don't think the pump/flow is your issue.

 

[Tehrab]

This image doesn't show the plumbing (I will post that tonight) but you can see how I have it baffled here with 1" seperation between baffle walls.

 

[rustybucket145]

why is your return pump in the middle chamber?

Also 1" is VERY slim for a bubble trap flowing that much water. The slimmest I've ever seen is 1 1/2". This allows the water to flow slower through the trap and gives the bubbles a chance to float to the top of the column.

 

[Tehrab]

<a href=showthread.php?s=&postid=9575068#post9575068 target=_blank>Originally posted</a> by rustybucket145
why is your return pump in the middle chamber?

Because I didn't want a linear flow in my sump. If and when I do get the fuge running, I want to split the drain between the two chambers.

<a href=showthread.php?s=&postid=9575068#post9575068 target=_blank>Originally posted</a> by rustybucket145
Also 1" is VERY slim for a bubble trap flowing that much water. The slimmest I've ever seen is 1 1/2". This allows the water to flow slower through the trap and gives the bubbles a chance to float to the top of the column.

This is what I feared. In leading up to the creation of my sump, it seemed every thread I read on the subject settled on the 1" mark as sufficient.