Enhanced Sump Design - Baffle Configuration

[abcha0s]

Wow. Awesome feedback guys. Thank you.

Dan - I think your right about the effect the teeth would have. As you suggest, micro bubbles are hard to deal with because they rise very slowly.

Originally Posted by Lampshade

If you have the water level close to that height in the return chamber then the raised baffle is great, mine lifted the flowing water another 3/4", creating more waterfall, creating more bubbles. If you had another "down" baffle you could get rid of this. It's what i plan on doing shortly, but need to figure out how small to make it so that it's functional

Lot's of good information here. I will elaborate on this in my clarifications below. I do have one question though...

Wouldn't the water level in the return chamber be set by the placement of your ATO level sensor? - To avoid this, the sensor for my ATO is about 1/3" above the baffle hieght. I get some ripples over the 3rd baffle, but no downward current.

Originally Posted by lastlight

Brad I like that idea. I think the downward suction is also due to the distance between baffles 1 and 2. The area of that gap determines what sort of pressure is created there I think. I'd use a greater distance between 1 and 2 and then experiment with lowering baffle 1. I think the horizontal distance will have more effect. As it is you are letting the bubbles get farther away from the surface as well so in my opinion a combination might be more effective.

Brett - You're right. The height of the 1st baffle is only half of the story. The distance between baffles is also a factor. However, in most sump builds, the distance between the baffles is already sufficient (generally between an 1" and 1.5"). This depends on the rate of flow of course.

Originally Posted by asmodeus

i ran my baffles the other way Brad. I went for length in stead of up and down. I get alot more crap building up too and its easier for me to clean.

Hi Mike - If you have the space, your approach works well. The challange is that our sump designs are often space limited. It's a bit of a game to see how much functional space we can fit inside. The result is often a narrow baffle section.

Let's work the same design but with the new ideas being discussed:

The first thing that we need to consider is the effect of "gph" through the sump. It stands to reason that the perfect baffle height and distance between baffles could only really be determined if the exact gph was know before designing the sump. It's easy to imagine that if only 10 gph was moved through the sump, this whole exercise would be moot.

Consider a traditional sump design (same height baffles) with 3000gph moving through it:



In this configuration, the water level will rise considerably above the height of the baffle. The downward force will be substantial.

Now consider that only 2000gph is moving through the sump:



... and finally, consider 1000gph moving through the sump:



As the gph decreases, the water level will also decrease. At 10 gph the water level may only be 1mm above the baffle.

In consideration of Brett's point, let's move the 1st and 2nd baffles closer together:



The water level will rise and the downward force will increase. However, the height of water above the third baffle will remain unchanged.

The perfect design - IMHO

First, you must know the height of point A. This is purely a factor of gph.



The measurement for distance B requires a little bit of guess work. It is also a factor of how wide the baffle section is. I would speculate that for most sumps a measurement of 1" or 1.5" would be sufficient. You could work this distance out experimentally by positioning a fourth baffle to the right of the 3rd baffle. With the sump running, move this fourth baffle closer to the 3rd baffle until the water level starts to rise. The point just before the water level rises is the ideal distance at point B.

B - A = C and is the height by which the 1st and 3rd baffles should differ.

The measurement for distance D is the optimal height at which to place the ATO level sensor if the intent is to minimize micro bubbles.

Note: The only problem with keeping the water level so high in the return section is that a protein film can build up on the surface. A little bit of a water fall and some agitation might not be a bad idea.

- Brad