Critique 18.5g FO design

[MKramer]

I've been planning a 18.5g tall fish-only tank with a built-in sump. I was curious to get people's comments on the way I designed the sump to see if I missed any major drawbacks.

 

First, a crude sketch is attached at the end. Unfortunately I cannot represent this design well from a single angle, so following is a more verbose description.

 

One piece of glass across the aquarium that stops 4" from the bottom. Another sheet behind that that is the entire height of the tank. Holes are drilled at the top on one half of this sheet to act as an overflow. The chamber behind that piece is divided in half with another piece that does not touch the bottom. The return pump would be placed in the side of the sump that does not have the overflow holes.

 

So it would work by having the pump push water out of its sump chamber,

which would draw water out from the bottom of the other sump chamber. New water would enter at the top through the overflow, which is drawn from the bottom of the tank (thanks to the first divider which doesn't reach

bottom).

 

I went with this design for a couple reasons. First, sicne water enters the tank at the top, by drawing it into the sump from the bottom, I'm creating quite a bit of flow in the main tank without having any powerheads or pumps visible. However, I still wanted the water to enter the sump through an overflow, partly to maximize the length of the sump chamber, partly to increase oxygenation of the water. I want this thing to be as quiet as possible, so I wanted to avoid splashing water back into the main tank, which would be about the only other way to effectively oxygenate such a tall tank. The first sump chamber will be filled with filter media like activated carbon and bioballs (this is a fish-only tank, without live rock), so the freshly oxygen-enriched water will flow over the bacteria-laden bioballs at a good rate, maximizing their efficiency.

 

The second chamber will probably be used to house, in addition to the

return pump (which can be fairly small, since it only has to pump over the

top of the dividers), a submersed heater, and macro-algae for further

nutrient absorbtion. Hopefully enough light will get passed the powerhead

to feed the algae. If the main lighting for the tank doesn't reach down

there very well, I'll add a second small bulb right over the sump in the

canopy.

 

Thoughts/suggestions?

[Dazureus]

I Love the idea of in tank filtration, so I built a nano with it. Your design is good, but if I understand your proposal correctly, the first chamber will be bioballs or carbon for oxegenization? For this to work more effectively, I would think that the water level in this chamber would have to be pretty low (perhaps the bottom of the baffle). This might cause some trouble with the pump since it might suck in some of those air bubbles. Also, if you have access to a router, you could cut slots for an overflow instead of holes so you could get some more surface skimming. It will help prevent surface film build up and improve oxygenation. Besides that, the design is great.

[jyoon951]

the design looks good, the only thing i might suggest is possibly a drip plate or somthing like that on the overflow side to distribute the water more evenly over the biomaterial or a sponge prefilter that may do the same thing.

 

also, don't know why you need two partitions side by side bisecting the tank. is one permanently fixed, and the other one removable?