Slanted Baffles?

[Mercer]

For a new sump I'm toying with the idea of putting the return pump in the middle and am investigating ways to deal handle an 8-10" drop silently. I couldn't find much information on slanted baffles anywhere as most people seem to just mount them vertically. At such a height I'm getting the feeling there's going to be an undesired waterfall effect. Using a slant seems to make sense (at least in my head!) so I thought I'd run this one by you fine folks.

Has anyone mounted their baffles similar to my slanted baffles in the below image? How did it turn out?

 

[RocketEngineer]

My first question is: Why do you have that much drop? To me that seems excessive.

My second question is: How much flow in what size tank? If the tank is wide enough you don't get a waterfall problem as surface tension is enough to keep the water on the baffle.

 

[sleepydoc]

I don't see any reason you can't. Installation will be trickier, and you effectively take more room out of the sump by doing so, but it should work, or at least help.

What's your sump design and desired flow? Why do you need such a large drop?

Why do you have 4 baffles? If you're trying to make a bubble trap, you only need 2 or 3, not 4.

 

[Mercer]

My first question is: Why do you have that much drop? To me that seems excessive.

To one side is the skimmer which sits in approximately 8" of water, and to the other is a much deeper refrigerium. The open area above the skimmer and return pump leave room to allow for a power failure and similarly the higher first baffle from the refrigerium side keeps any contents better in place. This setup assumes there's two drains one supplying each side.

My second question is: How much flow in what size tank? If the tank is wide enough you don't get a waterfall problem as surface tension is enough to keep the water on the baffle.

Working with a 75G that's approximately 17.5" wide internally. The flow won't be that insane and you're likely correct about the surface tension. I haven't worked out an exact flow rate just yet, but I'm thinking maybe 500-750gph from each end.

In addition to the slant it seemed as though the longer surface on the first refrigerium baffle could be used as a sort of algae scrubber as there will be a nice open 11x17" area open and easily lit by the refrigerium lighting.

At the very least I'm dying to try it and eager to see if someone can find fault with the idea!

 

[Mercer]

What's your sump design and desired flow? Why do you need such a large drop?

A lot of this is still on the drawing table. But overall a pretty basic layout inside a 75G tank.

Why do you have 4 baffles? If you're trying to make a bubble trap, you only need 2 or 3, not 4.

The 4 baffles were left over from a previous design I was playing with that stacked several vertical baffles of varying heights beside each to slowly lower the long drop. Think of each pair of baffles as dropping it another 1 or 2 inches. In this case it doesn't make much sense though and will likely only use 3 for each side.

 

[RocketEngineer]

My biggest issue would be trying to clean under it but if its in the refugium that won't be necessary. I run a 40B which is the same width but not as tall and in my case there is just the one baffle between the refugium and the center return. Even with a 6" drop, the flow rate is low enough that I don't have any bubble problems at all from that side of the sump.

For your setup, I don't see the need. My take is you're over thinking the problem when the simple solution will be more than satisfactory. JMO.

 

[sleepydoc]

+1
If it's just from a refugium over to the return section, you should only need one baffle. Many people don't even have baffles after their skimmer section.

If you have the time (and the pump,) you can mock up a system - just tape one baffle in place with some duct tape, fill with water and put the pump at one end pumping water into the other end. You should be able to get a feel for how much flow the system can handle before getting noisy.

 

[Bakerman]

That's what I did. Bubble trap on left (3 baffles), return in middle w/ an eheim 1260 return pump sitting on a 1/2" piece of rubber and plumbed with vinyl 1" ID hose, and a fuge on the right w/ one baffle. The baffles on either side of the return are slightly (just eyeballed) angled. Maybe 5 degrees off plumb. Also, the baffle edges are 45 deg chamfered on both sides. Totally silent, no turbulence, no bubbles. Worked perfectly!

 

[Mercer]

That's what I did. Bubble trap on left (3 baffles), return in middle w/ an eheim 1260 return pump sitting on a 1/2" piece of rubber and plumbed with vinyl 1" ID hose, and a fuge on the right w/ one baffle. The baffles on either side of the return are slightly (just eyeballed) angled. Maybe 5 degrees off plumb. Also, the baffle edges are 45 deg chamfered on both sides. Totally silent, no turbulence, no bubbles. Worked perfectly!

What sort of flow do you have on the go? What size sump? Any photos? I'm still thinking this is an engenius idea but it certainly differs from the standard 90° approach. It will also end up costing a fair bit of horizontal space to implement so I'm trying to choose wisely.

 

[Bakerman]

What sort of flow do you have on the go? What size sump? Any photos? I'm still thinking this is an engenius idea but it certainly differs from the standard 90° approach. It will also end up costing a fair bit of horizontal space to implement so I'm trying to choose wisely.

I'm still in closed loop mode (downstairs flow only) on the sump, so I don't know my final DT flow #'s. I do have a flowmeter inline, so I'll let you know. Shooting for ~200gph @ ~10' of head. That said, I think the baffles that you see here are probably taking about 450gph as shown since I'm not pumping upstairs. I want about 100gph through the skimmer (shown on left), about 75gph through the fuge, and the leftover will go back into the return.

As far as horizontal space, as you can see from my pics it takes up virtually no additional horizontal space. The baffles are just BARELY slant, which does the job perfectly well. I'd do it again in a heartbeat.