calling all upstream refugium owners

[Mihai]

I just finished installing my 20gal upstream refugium and started it.
To my complete surprise and horror (why, I should have know that any overflow produces bubbles ) my main tank got filled with bubbles.

The idea was to have lots of goodies (pods, eggs) from the refugium in my tank without chopping them through the return pump impeller.

It turns out that I have lots of bubbles.

My setup is as follows: tank 90gal, refugium 20 gal, sump 30 gal.
The sump is in the basement, feeding both the refugium and the main tank. The refugium has an overflow like any other tank that goes into the main tank. The overflow of the refugium has a Stockman pipe (a Durso modification) and that's what makes the bubbles. What can I do to get rid of it? I was thinking of a sort of a small separation chamber just at the entrance of the refugium overflow into the main tank, but I don't know how to do it...

Thanks a lot for the time and advice,
Mihai

 

[sawyerc]

Ahhh yes, the old bubble problem. I just went through this but for another reason. I finished setting up my basment sump and it ended up sounding like a hot tub because of all the bubbles. There are many threads on this and other forums about eliminating sump noise which means eliminating sump bubbles. You might find good information looking in that direction. The most common method is to restrict the flow slightly with a valve or a few elbows so that air can bubble up through your overflow before getting sucked down the tube. You back it up enough to reduce bubbles but not enough to overflow your refugium. Supposedly this is very possible, impossible though it seems. Personally I'm a redundancy nut and did not like to think of my SINGLE overflow being closed up a little bit. I ended up building essentially a muffler - a tube running horizontal right at the water level with lots of slits to allow the bubbles to escape. This, however, probably works better for noise reduction than bubble reduction. Others suggest putting a section of airline tubing down overflow and pulling it up until the bubbles stop. For me, this did not work. I would be that your best option would be the baffles. I can't unfortunately help you with this because I don't have any experience, but there are some explanations of various setups in threads devoted to sump noise. Best of luck,
Sawyer

 

[billyzbear]

I have a fug above my tank for the same reason as you. In front of my bulkhead I have a screen, no elbows. The bulkhead is 3/4 then I have a ball valve then it opens to a 1" hose to a elbow, then another elbow, then just to water line in tank. The first time I set it up I had a 3/4" port and reduced it to 1/2" line. I had a bunch of bubbles or suction would happen. But by making the line bigger allowed air in and no suction or bubbles. And I have no straight up and down, all slopes.

 

[Mihai]

But by making the line bigger allowed air in and no suction or bubbles

Really? it's that easy? I'll try that!

Others suggest putting a section of airline tubing down overflow and pulling it up until the bubbles stop.

That sounds like voodoo to me... is there any reason for this to work?!

This, however, probably works better for noise reduction than bubble reduction.

The sound is not that bad; the bubbles on the other hand... and actually it's not the bubbles that bother me, it's the salt creep that comes with them.

I would be that your best option would be the baffles

Well, something like that is what I had in mind, except that I don't want to build a huge structure in my display tank just the get rid of the bubbles from my refugium. My question was regarding the plans of such baffles..

I can't be the only one on this board with this problem: I bet that all upstream refugiums have this problem! .

Regards,
Mihai

 

[dizzy]

Mihai,
I have had a similar problem. I don't see how increasing the pipe size will eliminate air in the line. Going smaller could lead to overflow of the refugium unless a second drain line is installed that is cut off above the first to work only in an emergy when the water level gets to high.

Here is how I have addressed the problem: Say you had a 1" pipe coming down from the refugium and into the tank below. I bought a special coupling at Home Depot that increases the pipe size from 1" to 2" (or could decrease if mounted upside down) there at the top of the water level. I then use a 2" piece of pvc pipe that is not glued into the coupling to go down into the tank. I run it to within about an inch of the bottom. If your flow from the refugium is not to strong the bubbles will not make it all the way down to the bottom, as they tend to want to float up to the top, where they exhaust up and out the drain pipe that brought them in the first place. This pipe can be hidden from view by attaching small pieces of live rock with epoxy putty to its sides. Or just by placing live rock in front of it. Hope this helps.
Mitch

 

[Mihai]

Mitch,

I see your point of view. However, it resembles with what billyzbear is describing: he is increasing the pipe size from 3/4 to 1" (you increase from 1" to 2"). The main difference is that he does that "in the air", i.e., before it reaches the tank, while you do it "in the tank".

Conceptually I think that both work the same way: when the water gets from the small pipe to the large pipe it has lots more space to expand, and hence it gives the bubbles a chance to separate from the waterflow and get out (through the overflow).

The trick with submerging the pipe coming into my tank might further help as it probably keeps the 2" pipe all full of water and it further discourages the bubbles from going all the way down to the bottom of the tank to get out of the tank.

I'll see how I can try to hide it, I don't want an eyesore in my tank

I'll try it out.
Thanks a lot,
Mihai

 

[billyzbear]

Yes, it will work. If it doesn't decrease your water going in or increase the size of the bulkhead. On mine I only have a 1/2" line into a plastic pipe with holes drilled into it. I get no noise and no bubbles.
From my testing useing a Durso pipe is as soon as the air was out of the line it created suction and the rate out would increase. If the intake wasn't matched to the out air would get in stop the suction then all hell would break lose. I then put a small hole on the out to stop suction but this caused bubbles. I then found if my out is bigger than the in everything was golden.
From what I have read you only want a 1:1 turnover rate. Use only slopes and my out is only 3" or so above water line in tank.

 

[der_wille_zur_macht]

That sounds like voodoo to me... is there any reason for this to work?!

You think that sounds Voodoo? heh - I've got a voodoo solution for you. I happened upon it by trial and error trying to fix the same problem you're describing.

Basically, I put two 45 deg. elbows on the end of the 'fuge's drain line (into the display tank), skewed about 15 deg or so. The drain is a standard Durso with a very gentle slop down into the display tank.

This configuration, coupled with the flow rate I use, produces an interesting effect after about a day of operation. A single big air bubble forms in the kink between the two elbows and grows slowly in size until it just happens to be big enough to restirct the flow just the right amount so that no additional air needs to be sucked through the drain line. Until that point, the thing bubbles like mad. After that point (a day or so) only a very few bubbles escape from time to time.

With any drain line that's oversized, *some* air needs to get sucked all the way through to compensate for the extra capacity, or else you get a full-on siphon and water levels go crazy. Thus the stockman or durso pipes allow some air to enter, to make up for that extra capacity. In theory, we could just get an *exact* drain pipe size to match a given flow rate, but even a tiny fluctuation would throw things out of balance.

My oddball solution solves the problem by allowing the restriction (air bubble) to be dynamic in a sense - if the flow rate changes a bit for any reason (gunk in pipes, snail in pipe, etc) the air bubble gains or releases a bit of volume and compensates automatically.

I hope my explanation is clear enough. I'm not sure if this is even something that would be easy to duplicate or not, but I thought I'd dig up this old thread and mention it after struggling with this same problem for a long time myself.

edit - just re-read mitch's post until I understood it - sounds like we're using the same theory. Allow air bubbles into the drainpipe, but either let them get trapped or escape elsewhere instead of coming out the end into the display tank.

 

[Mihai]

That sounds like voodoo to me... is there any reason for this to work?!

You think that sounds Voodoo? heh - I've got a voodoo solution for you. I happened upon it by trial and error trying to fix the same problem you're describing.

Basically, I put two 45 deg. elbows on the end of the 'fuge's drain line (into the display tank), skewed about 15 deg or so. The drain is a standard Durso with a very gentle slop down into the display tank.

Actually this is the opposite of Voodoo . There is a logical explanation that even I could follow . My only question is on how did you place the two 45 degrees elbows in such a way that they hold the big bubble and not dump it in the tank...

I'm not sure if you can explain, or draw, but it would be of big help to me.

Thanks,
Mihai

 

[der_wille_zur_macht]

The drain meets the top of the tank at a bit less than 45 deg. down from vertical. So, the first 45 deg. bend points just back past vertical. The second bend, thus, points a little less than 45 deg. the other side of vertical.

Personally, I think Mitch's version would be simpler to duplicate. IMHO mine's more of a random chance thing - you could get two elbows and play around forever and maybe not get the same result. I'd take a picture but have no digital camera.

 

[Mihai]

Thanks, makes sense: you have a "hump" that collects air. I'll try mitch's version first.

Thanks,
Mihai