Over\Under\Over?

[BigJPDC]

Hello - sump building this weekend here.

I am looking for recommendations\advice on if it is preferred to go under-over-under with baffles or over-under-over?

I'm using a 20H, and will not have a fuge, just two compartments. One for the skimmer and the other for heaters and return.

thanks!
jp

 

[8BALL_99]

With 3 baffles then IMO Over Under Over does the best

 

[BigJPDC]

With over-under-over, wouldn't the final hop produce more bubbles since the water falls down to the return pump's section?

Or do you keep the water level above the final baffle so there isn't any waterfall action?

This is the part that is confusing for me.
jp

 

[Phyxius]

BigJPDC
All of my sumps(20L & 15) are done this way and so is my 30 I just finished today . Only difference is I have a refugium in the middle. The water drop can be lessened by your water level in the sump in the return pump area. If you keep it topped off so the level is pretty close to the height of the last baffle there wont be much of a drop. The other factor is how much flow you have going through the sump. Low flow and it will gently go over the edge of the baffle. High flow will create more of the waterfall action that could cause more bubbles.
Keeping the water level close to the height of the last baffle would be best bet.

 

[BigJPDC]

Awesome - thank you!

jp

 

[bigdee65]

I happen to like just the 2 baffles best. First one is over the the second under. This way there are no bubbles getting into the return section.

Here is a pic of mine:

 

[got2lb]

Mine is Under - over - Under That way it's not cascading down the last baffle to hit the water. Doesn't really make a dif. on mine by the time it get through the fuge there's no bubbles anyway!

I'll show you a picture as well.

 

[sjm817]

This is debatable. Both have their up and downs (LOL). U-O-U will prevent bubbles from going over the first baffle, but will not prevent low travelling bubbles from going under the first baffle.

O-U-O will prevent bubbles from going under the first baffle, but does not prevent them from going over the first baffle.

What is important is to keep the water moving slowly though the baffles. If it is screaming through, the bubbles will be pushed right through with no chance to rise and escape. This means:

Stay away from excessive sump flow. Less is better
Spread the baffles out. 1.5" or 2" will work better than 1"
Wide is better. Water will move more slowly over a 16" wide baffle than a 12" wide baffle.

My new sump is O-U-O-U, 16" wide baffles spaced 1.5" with ~ 400 GPH flow. It works well...but...

Tiny microbubbles are not buoyant. They dont float. The way a bubble trap works is bubbles float to the top when the water is travelling downward. If they dont float, they go right through.

 

[BigJPDC]

Outstanding information - thank you! I think I will start out with a two baffle setup, 2" apart, O-U. I'll do some flow testing and decide if I want to put the third one in on either side, or not at all.

I think my glass shop just bent me over - $25 for three 1/4" 9 x 11.75 pieces.

jp

 

[vanceny]

fyi - you won't get the same results for the baffles when running it in fresh water since there will much more bubbles in salt water.

 

[aquawolf]

Thanks everyone, you have also helped me out as I contemplate building my own sump/fuge to replace my tidepool wet/dry.

 

[areze]

one thing I heard, the under-over-under this doesnt provide any agitation to the surface of the return side. it can get a nasty film.

 

[got2lb]

<a href=showthread.php?s=&postid=6710448#post6710448 target=_blank>Originally posted</a> by areze
one thing I heard, the under-over-under this doesnt provide any agitation to the surface of the return side. it can get a nasty film.

If you notice on my picture above I have my pump bypassed since it's too big and it keeps the return agitated.


NO NASTY FILM!

 

[ejmeier]

<a href=showthread.php?s=&postid=6709564#post6709564 target=_blank>Originally posted</a> by sjm817
My new sump is O-U-O-U, 16" wide baffles spaced 1.5" with ~ 400 GPH flow. It works well...but...

Tiny microbubbles are not buoyant. They dont float. The way a bubble trap works is bubbles float to the top when the water is travelling downward. If they dont float, they go right through.

What if on one of the OVER baffles, you put a piece of glass horizontally at the top, maybe rising on a slight angle. That way, it would let all the bubbles 'pan out' and hopefully pop at the top as they glide horizontally for a few inches.

Kinda like this:

water flows
this way --->
____
|
|
|
|

If that even makes sense...

 

[sjm817]

Very interesting idea! It seems like it would help.

 

[suprzman]

ejmeier,
that actually does make sense, the only thing would be that the water should not fall very far once it goes over that ledge, otherwise it would just create new bubbles. so if there is a fuge in the middle section, then the baffles at the end of the fuge should basically be just the tiniest bit shorter than the baffles at the beginning of the fuge section. therefore only a very slight drop is made, and new bubbles arent formed.

 

[ejmeier]

Heh, I haven't tried it, but it seems like it would make sense and work to my brain.

Yeah, I thought about the bubbles falling too far too. You could also angle it up slightly and then down. (Though I bet just making them travel 90d sideways would be enough.) You could even cut a piece of larger dia PVC/ABS (maybe 2 - 4") and then cut it lengthwise, then you would have a nice arc for the bubbles to slide up - and then down gradually - back into the sump's water.

Like this:

/----\
|
|

:lol: okay, THAT little pic was pretty lame, sorry - too lazy to do it in paint.

 

[xcreonx]

Over was over-under and under was over-done

sorry, that was no help :rollface:

 

[BigJPDC]

mission accomplished

mission accomplished

Well, this turned out to be harder than it sounded like it was going to be. My job doesn't look as good as most I see here on RC, but they appear to be good and tight. The biggest challenges was figuring out how to bead, tool and then later cut in between the baffles.

Masking . . .

. . . and finished in the stand.

I also got my doors roughed out. 17 inches of snow has a way of keeping you focussed I guess. =)

jp