Baffle placement for a 90g sump

[mille239]

I am converting a 90g tank into a sump. Am thinking of two sets of 3 baffles (in an over-under-over orientation per set) for bubble traps, and a place to keep chem. media. The sump will be running roughly 1000gph through.

How far apart should the baffles be from each other? (1" 2" 3"?)
How far off the bottom should the middle baffle of each trap be positioned?

Thanks in advance for any advice!

(very basic sketch)

 

[mille239]

Bump. Anyone?

 

[KDodds]

I designed pretty much the same thing on my 180g sump. It's worked very well for me, actually. My first and last "compartments" are 6" from the walls. The middle (raised) baffles are 3" from thos and 3" off the floor. The next are 3" from the raised baffles. BUT, I have a throughput of around 5000gph. I would not impede the flow at the baffles, especially if the middle section is going to contain a refugium. There's too much risk that something can build up or break free and clog this "bottleneck". I use the first and last compartments for large media, but do place 100ml Purigen bags between baffles (because they're so small they can sit on the floor and not risk impeding flow). BTW, the flow pattern of this setup makes for an ideal central refugium. Just make sure that you have the water level high enough over the last baffle, or the last section large enough, that it doesn't produce a "water fall" effect should the pump drain the last compartment too quickly. This is why most designs have the last baffle as a floor baffle lower than all others or a raised baffle.

 

[mille239]

That's a lot of flow through there, woah! Thanks for the advice... will plan on 3" spacing.

Also, in the first compartment of the sump, where the overflows drain into, would it be to an advantage to keep some extra live rock in there, or leave it empty for easy cleaning of ditritus that collects?

 

[KDodds]

I'm leaving teh "dump" compartment empty since that's where I'm feeding to my skimmer. It serves as well as a "settling chamber" to some extent. I'd put any LR/refugium/macroalgae/etc. in the center compartment.

 

[mille239]

Excellent. Thanks again!

 

[KDodds]

NP. BTW, 3" would be WAY overkill for your situation. I think safe minimums would be about 4-6" in the first and last compartments, and 1Ã"šÃ‚½-2" between baffles. That is, if you want to leave a little more room in the center (which will serve either as a settling chamber or refugium), otherwise, no harm in making the larger, really, other than you want the "up areas" to have a little more "push" to get air to the surface.