I want to build a cheap and easy turf algea filter, primarily to knock down N and P. After reading about the superior nutrient uptake of turf algea compared to other macros, and after seeing that there are really no units for sale anywhere, I thought I'd see what I could (easily) build myself in about a day. After all, we are just trying to get water to splash across a screen that is lit up. It's shouldn't be this hard to do.
So I came to realize the hardest thing to build would be the device that sloshes the water across the screen; the two prevailing methods were a dump bucket, and a rotating wheel. Both seemed difficult to build. So I thought, those methods are going through a lot of work to get water from point A to point B; why not just let the water fall on it's own (like a waterfall)? Think vertical, instead of horizontal.
So the idea came to just tilt the screen up vertically, and let the water slosh down the screen. Here are the advantages to building a waterfall version of a turf algea filter instead of one of the other versions:
o The turf algea screen can be lit from BOTH SIDES.
o Extremely simple design, about as complex as a HOB overflow (and may even be able to use the same HOB box.)
o There are NO MOVING PARTS at all.
o You get to choose any (low cost) water pump size you wish, and keep it wherever you wish (sump or otherwise).
o You get choose to have the pump on continuously (very easy to do), or pulsed with a timer to simulate waves.
o You don't have to move or turn off the lights to get to and scrape the screen; just slide the screen up out of the box.
o The unit can fit right over (and drain into) a sump if desired.
o There is NO dumping-bucket to build or deal with or wear out.
o There is NO rotating wheel or drum to build or deal with or wear out.
o There is NOTHING to break or clog.
o VERY cheap and EASY to build (main item required: a square acrylic box.)
o Theoretically, would have no no dumping sound to listen to.
o Theoretically, would have no microbubbles.
o Theoretically, would be half the size of a one-sided filter (since it is lit from both sides).
Drawbacks:
Not designed to provide a surge to display tank.
Not designed to douse the screen with high-velocity water (like a dumping bucket would).
May give tint to water; may need carbon to clear it.
"Open" Option:
For an even easier setup that is almost free to build (all that is needed is a pvc tube with holes or a slit in it), you can just not use a box at all, by just placing the screen vertically over your sump, and use your existing sump/fuge lighting (or else add small light on both sides of the screen. This version might not be as effective since the lights may not be as bright (or as near). And you'll need to figure out how to attach the spraybar to the top of the screen. But talk about simple! You don't have to open anything at all in order to scrape the screen!
Anyway, remember that I have not built this yet, since I wanted to get input first. My current tank is about 100 gal, and I seem to remember a recomemdation of once square inch of screen per gal, so that would be 100 square inches for me (10 X 10). Pretty small. But the two big unknowns are: Can it be smaller since it's lit on both sides, and, will it perform less since the water will not be "surging" as much.
Here's the basic cutout of an acrylic box, is open on the top, and closed on the bottom. Note the drain hole on the bottom too:
Add the algea screen; could be held in place with a slot or rail or pegs:
Add the spraybar over the top; a piece of pvc drilled on the bottom, or slit from one side to the other. It fits in the the circular cutouts in the box:
A standard light, placed vertically; this one is facing towards you:
A standard light, placed vertically; this one is facing away from you:
Both lights:
This is how the lights would be attached to the box:
