Acrylics Project - Algae Scrubber w/e-Shine LED fixtures for 4 cube/day feeding

I've been keeping this one kind of under my hat as I build it.  This is my prototype scrubber that uses the e-Shine 50W LED grow bar fixtures.  The box is about 95% complete.  I have to drill and tap a few holes, and add some gussets inside the box for a false bottom support, route holes and/or slots for the power cords, and make the lid.


Here's some rough cut pieces

The bottom panel



End panel with slot for 3/4" Sched-40 PVC slot pipe



Top lids



Assembly pics




The box is all 1/4" cell cast Plexiglas brand, except for the black cutout windows which are 1/8" extruded and are just tack welded in place (since the windows are the structural part)


The "Diet Barq's" technique



Brackets for supporting the fixtures



The fixture is a perfect fit!



The little squares will get drilled and tapped for plastic thumbscrews, which will hold this bracket in place




This bracket serves the purpose of both holding the fixture sung in the box frame (via thumbscrews) and also provides the means for protecting the fan intakes from moisture. The holes are cut out to provide a space to insert a thin piece of foam (like the Poret stuff) that is intended to catch any salt spray, stray water droplets, or (to a lesser extent) evap moisture from getting to the fan and thus getting blown through the fixture.


The top rail of the bracket is designed so that it leaves a gap above and below so that air convection is unimpeded as it exits out of the vents on the top and bottom of the fixture. There will also be a drip lip along the top edge of the box so that if any water gets spilled on the top, it won't wick under and drip onto the fixture


I still have to make the slot pipe assembly and rough the screen up, etc etc.


The next one of these I build will probably have a changes, only minor modifications though. The fixtures will be black instead of white, and they will have connectors on both ends so they may be daisy-chained (I didn't know you had to ask for that option).


I used this design as the basis for the custom LED 1 cube/day and 2 cube/day scrubbers I am working on. Those are up next. After I start bonding the pieces for the 3 tank projects, I will have lots of 'wait' time to fill.

 

Drilled & tapped







Thumbscrews hold it all together



Holes drilled for fixture power cords





Windows for fixtures





LET THERE BE LIGHT!!!









Youtube video

http://www.youtube.com/watch?v=mXpz7rf771k

I have to say that I was very impressed myself with how little light is bled out of this box. I have a feeling this is going to be a very good scrubber.

 

45x 660nm Deep Red and 5x 455nm Royal Blue. Any LED grow light you see looks like this.

 

I will be shipped off by then, but i should have others being built

 

Been a while since I updated this thread. I finished it off and shipped it. Right now he's ramping it up...unfortunately yesterday he shut the pump off to check the screen and forgot to turn it back on, so the screen died.

uniseal



Street elbow



inside



standoffs for false bottom



clear false bottom to test



slot tube



I tried making little diverters to cause the water to circulate down the drain. These are just double-stick taped on. I didn't end up using the concept, it didn't make a difference.







Finished box





black false bottom



installed



o-ring for power cord to seal off hole



I added holes on the other side so you could put the fixtures in however it made sense, and these plugs fit the holes you don't use perfectly



all the parts (including the lid)



with lid on



Custom made box (made from a 4x8 sheet)



foam board and peanuts packing technique









Top and fixture holder brackets



Got it all in there, including the slot tube, screen, pump, and all other parts.



It arrived alive and is up and running on his system.

 

I made a series of YouTube videos while I was testing the noise silencing issue. What it comes down to is that the false bottom alone (with no airline even) keeps it pretty quiet. With the adjustable pump, you can tune it just right so it only "slurps" ever now and then, and apparently after running it for a few days, it hardly even does that.

 

Because of all the extra parts needed for the fan-driven light fixture, I don't think I would make another one for any less than $500. I would rather make one on a big heat sink and use 3W LEDs and no fans. But possibly would do a bunch of 1W LEDs on a heat sink. I hated making all the 1" and 2" squares, fingers just too close to router blades for comfort.

 

You screen is way too big. 20x40 = 800 sq in. The new screen sizing guideline is based on feeding not tank volume. You only need 12 square inches of screen lit on both sides (12 watts total per 12 square inches) for each cube of food fed per day, or equivalent thereof. When it comes to scrubbers, bigger is not better, because the algae spreads out and gets starved and turns yellow, which does not filter as efficiently as green. Your screen, properly lit (which would take 800 watts) is big enough to filter over 65 cubes/day. If it is underlit (which I'm guessing it is) it will grow even less efficiently. If you're feeding over 10 cubes/day, you still only need a screen that is maybe big enough for 15, which is 180 sq in, or 1/4 the size that you have now.

As far as slot tube size, 3/4" should be fine, I have used 1" in the past. Uneven flow between each side is usually because the screen is not hanging perfectly perpendicular, which means the screen will be up against one side of the slot and the flow will naturally push to the other side. I am pretty anal about getting the slot facing straight down after cleaning. Also if the slot is particularly long, the tube will tend to pinch closed under the long distance of the slot, another reason to limit the length of the scrubber. You can also inadvertently pinch the slot closed by cinching down on the zip tie too hard. The screen should hang loosely in the slot and as close to vertical as possible. A slot that is not perfectly straight will also result in restricted flow to one side, or spots on a side.

Also flow rate does have something to do with it. If your flow is too low for a particular slot, the water will not make it to the end of the tube and will tend to "arc" on the inlet side of the tube, leaving the side closest to the water input bare. Usually when the screen fills in, this will lessen. But getting the flow at 35 GPH/in of screen and a proper slot width will fill the entire pipe and force the water to cascade down the screen evenly. Conversely, if a flow rate is too high, it will spray from the slot an go all over the place.

As for spacing, with 1W DIY LEDs you pretty much have to put them right next to each other. for 3W LEDs I suggest a 2" spacing so that each LED covers about 4 sq in of screen and then run them at around 2W power of 700mA roughly. 3" from the screen is a good distance to use. Putting them closer can cause burning, but since LEDs are tuned to the spectrum that algae likes (660 and 455 in 6:1 or 8:1 ratio) you need less wattage and less hours, so you probably could get them closer and be OK, might need a diffuser to spread the light out a bit and knock the intensity down slightly right in front of the LED. These are things I am working on refining.

Also I am learning (from the e-shine install and my own experiences) that since LEDs tend to almost exclusively grow green algae, there is much less initial brown diatom growth in front of the LEDS that is generally associated with the initial ramp-up period of the screen. More of the initial growth is around the periphery of the screen. Way back when, the temporary solution to the black slime growth was to put extra light on the screen to power through it. This evolved to doing 2x the light and 1/2 the time for regular use (this is the "high light" method). With a brand new screen and LEDs, it may very well be that only a few hours/day is enough to get the screen started, and any more could prevent the brown diatom initial growth. However this may not matter as all we really care about is the green hair algae.

Anyways that's my rant for the day. Issa just scale your screen way down and you will be better off.