Baffles - over under OR under over

[emm0909]

I am putting some baffles in my sump and wanted to see what other people thought about the order to put the two. Through these baffles water will be moving from the overflow/skimmer section into the return section.

Over/Under would draw bubbles from the skimmer into the trap but the water would be calm moving into the return chamber.

Under/Over would draw less bubbles into the trap but would have water overflowing into the return area causing turbulence.

I know three baffles would be the best but that's just not going to happen.

 

[madcowz]

I have only 2 baffles also under/over.

 

[hebygb]

I have two baffles before the return, and mine go over then under... no bubbles... ever

 

[ChknWing]

I had two baffles in a 10 gallon sump and they were under over and didn't have a problem with bubbles

 

[hobogato]

either will work, but if you go under over, round the top edge of the second baffle with a router and the water will flow over it much more smoothly.

 

[emm0909]

Great idea. Thanks for that tip.

So it's pretty much personal preference and to how I want to set it up.

 

[PAZE]

I have 3 baffles over, under, over, works great

 

[therealfatman]

As long as there are convolutions it does not matter. An effective bubble buster can be made with a maze like path way where the water just stays between the panels and never goes under or over them. Actually most mazes, if using the same amount of space, work much better but they require more glass and tighter work spaces with more seams.

 

[rbnice1]

Mine comes from the skimmer/return section with Over,Under,Over.

Then through a center section with liver rubble. Then Under,Over into the return section.

 

[drummereef]

My vote is for under/over. Reason being is bubbles will always rise. If they are forced to go over the last baffle then there's more of a chance they will just hit the surface and pop. That way even if there is a bit of turbulence it will be at the surface, not down where the suction side of the pump is.

 

[spleify]

All my sumps are, and have been over under over.

 

[hobogato]

i agree, but he only wants two baffles

<a href=showthread.php?s=&postid=14887489#post14887489 target=_blank>Originally posted</a> by spleify
All my sumps are, and have been over under over.

 

[emm0909]

Well I went over to Blacks Hardware on East Ridge Road the other day and had some glass cut up for the sump. They had 140 windows that they had to do but the guy still cut it for me right there while I waited. Cost-$11.50 for two pieces.

I'm not too sure on my choice of glass now and I can't believe how heavy it is. I have 1/4" plate glass cut to 11.875 X 10 to fit into a 20 gal. Now I'm afraid the silicone wont hold it in place forever. Nuts. Anyone use 1/4" glass in a sump?

Another issue is that the edges are unfinished. I'm going to have to hit them with some wet sand paper because they are so sharp.

 

[spw4949]

I actually bought some 8"x10" lexan from home depot for $3.50 per pice, it fits perfectly in my 10 gal sump, they had all sorts of differesnt sizes, for future reference.

 

[emm0909]

When I first started I heard so much from people about how acrylic wont bond with the glass. I figured it was a difference in the silicone needed. I wanted a nice bead of silicone down the edge instead of a sloppy mess so I thought I would make it all glass. I saw the glass pieces at Home Depot (Discontinued now so if you want them go get them fast) but they were only 3/32. I didn't think that would be thick enough so I just had some cut.

I plan on making it this weekend so I'll try to take pictures and post on here.

 

[boz151]

The issue with 2 baffles and the under then over arrangement is that if the section after the last baffle (over) becomes low from evap, the pouring of the water over the last baffle creates more bubbles in the area where your return pump is drawing h2o from.

 

[emm0909]

Makes sense. I'm putting an ATO in that section so the tank should be fine.

I put the baffles in this weekend. They came out pretty good. Sorry, no pictures. I'll get one sometime between now and when this thread is completely forgotten. I'm going to work on the ATO bracket and seal that in when I find the time. After that it'll just be a little drilling in the hardwood floors and I can set everything up.

 

[rickztahone]

The issue with 2 baffles and the under then over arrangement is that if the section after the last baffle (over) becomes low from evap, the pouring of the water over the last baffle creates more bubbles in the area where your return pump is drawing h2o from.

I'm sorry to resurrect an old thread, but you raise a good point. I am planning on finishing up a 3 baffle sump this week and was thinking of going over/under/over. However, what makes me hesitate is the first chamber having an under/over/under. I am doing a Bean Animal setup and I know that the siphon line has to be ~1" submerged. Being that the first section is an under, how do you control the height of the water line? I wanted over in the first section because that would always be a constant on the height it must go over from the first section. Any advice is appreciated.

 

[sleepydoc]

Water levels are always set by the 'over' baffles. For each chamber, the water level will be set by the highest baffle before the next chamber (assuming only one exit path for the water.)

Evaporation level changes always occur in the final/return pump chamber. The distance the water falls from the previous chamber to the return chamber is determined by the height of the last 'over' baffle, no matter where it is placed. If you place another 'under' baffle after that, the water level between the two baffles will fall to the same level as in the chamber and the water will fall the same distance.

In my previous sump, I had 3 chambers: Drain/skimmer, 'fuge,' and return. There was a single baffle after the skimmer section, and an under-over configuration between the middle and return sections. What I observed was that water would fall over the first baffle, then tend to continue down, along the floor of the middle section and under the first baffle to go up and over the 2nd baffle into the return chamber. The result was relatively stagnant water in the middle section.

In the return section, many have an ell on their pumps so they take water from close to the floor, so if the last baffle is an 'under' baffle, it can lead to stagnation in the return chamber. For this reason I advocate and over under over setup if you choose to use a bubble trap setup. IME, depending on your skimmer and other factors, they frequently aren't necessary at all.

 

[rickztahone]

Water levels are always set by the 'over' baffles. For each chamber, the water level will be set by the highest baffle before the next chamber (assuming only one exit path for the water.)

Evaporation level changes always occur in the final/return pump chamber. The distance the water falls from the previous chamber to the return chamber is determined by the height of the last 'over' baffle, no matter where it is placed. If you place another 'under' baffle after that, the water level between the two baffles will fall to the same level as in the chamber and the water will fall the same distance.

In my previous sump, I had 3 chambers: Drain/skimmer, 'fuge,' and return. There was a single baffle after the skimmer section, and an under-over configuration between the middle and return sections. What I observed was that water would fall over the first baffle, then tend to continue down, along the floor of the middle section and under the first baffle to go up and over the 2nd baffle into the return chamber. The result was relatively stagnant water in the middle section.

In the return section, many have an ell on their pumps so they take water from close to the floor, so if the last baffle is an 'under' baffle, it can lead to stagnation in the return chamber. For this reason I advocate and over under over setup if you choose to use a bubble trap setup. IME, depending on your skimmer and other factors, they frequently aren't necessary at all.

No bubble trap for me, and as I was reading your reply it totally made sense to me. Thank you for explaining it. I think I will go with my original over/under/over in to the pump section idea. I wouldn't want stagnant areas in the sump. Additionally, my return section will be pretty large, about 18"x11"x16". If my math is right, that is roughly 13g.