Current bubble traps have me baffled

16095 Views 14 Replies 9 Participants Last post by lewisrassel, 8 d ago

rhouse24

Discussion Starter · Sep 24, 2010

3

Note:
1) At the time of creating post I have never built a sump before so my ideas are all theoretical.
2)Lets not debate the necessity of bubble traps as some well designed sumps my not require them at all.

I would like to discuss bubble trap design and function.... and propose a change
This is the standard bubble trap (pic from melevsreef.com)

The goal of the bubble trap is to remove micro bubbles, slow turbulent water and keep the water level constant.

But IMO the current design is very inefficient and ineffective.
1) For starters a "dual trap" only traps bubbles in one area
2) The bubbles are pushed through the system
3) The velocity of the water is not effectively slowed
4) The first baffle injects the highest bubble concentrated water

Here's my ideas:
1) the first baffle should always pass the water underneath
reason: this draws water from the bottom of the chamber (where there are the least bubbles)

2) the distance between each baffle should be greater than the one before it.
reason: as the volume increases the flow rate will decrease creating calmer flow and giving the bubbles more time to rise.

3) relate the gap under the baffles to the baffle to baffle gap size.
reason: this removes restrictions in flow.

Diagram

Like I said this is all theory right now but I wanted to bring the ideas to mireefers to prove out

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spieg

· #2 · Sep 24, 2010

Thats the difference between an over-under-over and an under-over-under. It can be done either way. If your sump is long enough, skip the hassle of bubble traps alltogether. They are really only needed when you have a lot of chaos in a sump creating bubble problems.

rhouse24

Discussion Starter · #3 · Sep 25, 2010

spieg said:
Thats the difference between an over-under-over and an under-over-under. It can be done either way.

I am saying the over-under-over should never be used and that the gap between each baffle should increase with each baffle.

spieg

· #4 · Sep 25, 2010

Sometimes one works better than the other. If you have a refugium with sand in it next to a bubble trap, the under-over-under type doesnt really work. I think the general idea with either method is that the bubbles make it to the surface behind the middle piece of glass. While increasing the distance between would probably quiet the flow somewhat, the majority of the bubbles are already gone by then anyway. Thats not to say its not more efficient for the perfectionist, just that most people are more concerned with the 95%+ of the bubbles that get stopped by the first stop than they are with eliminating the 5% that make it through. In practice, both methods work, as does skipping them alltogether if your sump has the space and/or a low enough turnover. -yes

rhouse24

Discussion Starter · #5 · Sep 25, 2010

spieg said:
Sometimes one works better than the other. If you have a refugium with sand in it next to a bubble trap, the under-over-under type doesnt really work. I think the general idea with either method is that the bubbles make it to the surface behind the middle piece of glass. While increasing the distance between would probably quiet the flow somewhat, the majority of the bubbles are already gone by then anyway. Thats not to say its not more efficient for the perfectionist, just that most people are more concerned with the 95%+ of the bubbles that get stopped by the first stop than they are with eliminating the 5% that make it through. In practice, both methods work, as does skipping them alltogether if your sump has the space and/or a low enough turnover. -yes

You're right about the sand, but I think it's rare to have sand in the first chamber. Please understand this topic IS about efficiency, ask anyone if they would be okay with 5% of the micro bubbles from their skimmer getting in their display tank:no: I realize not all sumps require bubble traps, it was the second sentence of my initial post. If I could get people to learn two things from this it would be:
1: the first baffle (assuming its coming from a bare bottom chamber) should make the water pass underneath it. It is ridiculous to feed a system designed to remove bubbles with water that has the highest bubble concentration.
2: The baffles need to be spaced further apart, otherwise the bubbles get sucked through the trap.

spieg

· #6 · Sep 25, 2010

Im all for thinking outside the box and coming up with new ideas, dont get me wrong. Sand isnt the only example. Some people use the over-under-over method so that they can more easily tumble chaeto in the next chamber. Some people dont want to use filter socks but dont want detritus passing beyond their first chamber. Some people have zones established in sumps that they dont want the flow to disturb the bottom of the tank. There are a lot more scenarios that would make one setup more suitable than the other. All im saying is, its a pretty bold statement to say that its ridiculous to do it any way other than yours when youve openly admitted to never even building a sump. As far as the spacing of the baffles, it just depends on your setup. If youre only flowing 100gph through an 18" wide sump, 1/2" spacing is overkill. And doubling the second spacing to 1" will have little if any impact. If youre pushing 1500gph, 1" might not be enough, and while doubling the spacing on the second one might slow things down a little bit, having them both at 2" would likely yield better results. And 4" would be better yet. And 8" better yet. All the way until you get rid of the bubble trap alltogether. If this thread is about efficiency, you shouldnt start out by ruling out the most efficient method (good sump design with no bubble traps needed).

If I had any advice for anyone it would be:

Always keep it as simple as you can. Never limit yourself to doing things one way. There are numerous ways to have a successful setup.

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risedrummer

· #7 · Sep 25, 2010

I never saw any of this before I built my sump years ago, and I "figured out" the under over under method and never have had bubble issues. If you are going to do a 'fuge, do it the right way and have a second altogether. It's a lot easier. I've been trying to think of a way to make the water spin from fast tight flow and spiral out to slow wide flow and let the bubbles fade out as it makes its way through the "maze". That is a work in progress.

rhouse24

Discussion Starter · #8 · Sep 25, 2010

risedrummer said:
I never saw any of this before I built my sump years ago, and I "figured out" the under over under method and never have had bubble issues. If you are going to do a 'fuge, do it the right way and have a second altogether. It's a lot easier. I've been trying to think of a way to make the water spin from fast tight flow and spiral out to slow wide flow and let the bubbles fade out as it makes its way through the "maze". That is a work in progress.

Yeah, it's common sense, that's why it was so surprising when all the d-i-y plans say to go over-under-over.

Creating a spiral; you could try (with plexiglass) bending the top around like a shepherds staff that might work to get a vortex going.

BoBilo

· #9 · Sep 27, 2010

I have an over under over setup in mine and find it to work just fine. The next area is the fuge with sand/rock/macroalgae followed by a return area. My flow is very minimal and I have no bubble problems at all. To be honest I can't think of any reasoning for either design to be more succesful.

My previous sump had a first area under and then over and then over again (because the previous baffles were moving water from front to back) and then under over and into a fuge and then return section. I found it to be more of a pain in the butt to silicone it all in place then for it to be effective for what I made it to do.

If someone made a sump that allowed no dietrus build up I would do that!

streetrodder007

· #10 · Sep 27, 2010

It seems to me both ways of the bubble trap work. I don't see an advantage to either one over the other. I personally don't use a bubble trap, and I have found my filter sock on the the drain and a enkamat sponge on my return pump inlet to be the best bubble traps tools to work. 0 bubbles.

rhouse24

Discussion Starter · #11 · Oct 3, 2010

Surfactants

I got around to building a model yesterday

While I've got to give it more time, I see a huge problem with the under/over design. If the surface of the water in the compartment is not turbulent, surfactants build up very rapidly. They quickly accumulate on the downstream baffle forming a thick scum layer, oops:2911:

jahorgos

· #12 · Oct 3, 2010

I have always thought that the under over under method seemed to be better but with no scientific proof. I also though that adding a 4th baffle might be good, but maybe more practicle for the over under over under. Of course I dream of a sump that has no baffles with zero bubbles, actually I just dream of zero bubbles.

cutty

· #13 · Jun 15, 2020

rhouse24 said:
I got around to building a model yesterday While I've got to give it more time, I see a huge problem with the under/over design. If the surface of the water in the compartment is not turbulent, surfactants build up very rapidly. They quickly accumulate on the downstream baffle forming a thick scum layer, oops:2911:

I have been searching for ages for someone to address the over under over v under over under debate. I was definitely siding on the less popular under over under - because it doesn't make sense to draw water in from the most bubble prone area. However, I never thought about the build up on the surface, from restricting the flow through. You are right, this would likely result in surfuctant build up. This must be the reason for the more utilized over under over method.

richarddevis3

· #14 · Jul 1, 2020

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lewisrassel

· #15 · 8 d ago (Edited)

It can be done either way. If your sump is long enough, skip the hassle of bubble traps alltogether.

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