Algae Scrubber Basics

[Jade5051]

White reflects light and black absorbs light. So, why are so many algae scrubbers made with black acrylic?

[AZRippster]

You don't want algae growing where you don't want it growing. For example, the waterfall pipe groove, bad place. Bottom line, you want algae to grow on the mesh, if possible, no where else.

[SantaMonica]

Because adding white to the black is a hard extra step.

[ecotanker]

White acrylic will let some light through. It does not reflect all of the light back. One person on the algae scrubbing forum has build a scrubber with white acrylic and that is what they observed.

Originally Posted by Jade5051

White reflects light and black absorbs light. So, why are so many algae scrubbers made with black acrylic?

[biecacka]

So for my screen how many CFL bulbs per side? How many LEDs? Screen is about 12x8. And maybe a link to some bulbs to start. Like from HD. Or par 38 type LEDs they gave or Amazon maybe.
Thanks
Corey

[AZRippster]

Originally Posted by ecotanker

White acrylic will let some light through. It does not reflect all of the light back. One person on the algae scrubbing forum has build a scrubber with white acrylic and that is what they observed.

This must be some form of semi translucent white acrylic. I've worked with white acrylic several times in the past and none of what I worked with would allow light through, at least in 1/4".

[Jade5051]

Where do I get crushed Quartz for a small UAS? Or is there something else I should use and is easier/cheaper to find?

[Jade5051]

Can't I use crushed glass instead of Quartz?

[karimwassef]

I find MH to be great for lighting a scrubber.

[mattberrytr]

Originally Posted by AZRippster

This must be some form of semi translucent white acrylic. I've worked with white acrylic several times in the past and none of what I worked with would allow light through, at least in 1/4".

I think they may have been referring to a scrubber I built. It uses 4.5mm 'opaque' white acrylic. To the eye it is completely solid white, however it does let a lot of light through when you have high powered LEDs pumping light into it. I doubt going to 6mm (1/4) will be enough, I think you'll need to bump it up to 8mm at least.

The same 4.5mm acrylic, but in black, completely blocks all light.

[mattberrytr]

Originally Posted by Jade5051

Can't I use crushed glass instead of Quartz?

You could try using aragonite sand.

[Jade5051]

I think the purpose is to just create a rough durable surface that can retain some of the algae after cleaning.

[SantaMonica]

White acrylic will let some light through

Not acrylic; a white coating on the black acrylic.

Where do I get crushed Quartz for a small UAS? Or is there something else I should use and is easier/cheaper to find?

Fine gravel is good and easy for most people; just not as bright.

how many CFL bulbs per side? How many LEDs? Screen is about 12x8

Here is a guide;

Scrubbers are sized according to feeding. Nutrients "in" (feeding) must equal nutrients "out" (scrubber growth), no matter how many gallons or liters you have. (However each 50 pounds of problem rock adds 1 cube a day)

So...

An example VERTICAL upflow or waterfall screen size is 3 X 4 inches = 12 square inches of screen (7.5 X 10 cm = 75 sq cm) with a total of 12 real watts (not equivalent) of fluorescent light for 18 hours a day. If all 12 watts are on one side, it is a 1-sided screen. If 6 watts are on each side, it is a 2-sided screen, but the total is still 12 watts for 18 hours a day. This screen size and wattage should be able to handle the following amounts of daily feeding:

1 frozen cube per day (2-sided screen), or
1/2 frozen cube per day (1-sided screen), or
10 pinches of flake food per day (2-sided screen), or
5 pinches of flake food per day (1-sided screen), or
10 square inches (60 sq cm) of nori per day (2-sided screen), or
5 square inches (30 sq cm) of nori per day (1-sided screen), or
0.1 dry ounce (2.8 grams) of pellet food per day (2-sided screen), or
0.05 dry ounce (1.4 grams) of pellet food per day (1-sided screen)

High-wattage technique: Double the wattage, and cut the hours in half (to 9 per day). This will get brown screens to grow green much faster. Thus the example above would be 12 watts on each side, for a total of 24 watts, but for only 9 hours per day. If growth starts to turn YELLOW, then increase the flow, or add iron, or reduce the number of hours. And since the bulbs are operating for 9 hours instead of 18, they will last 6 months instead of 3 months.

HORIZONTAL screens: Multiply the screen size by 4, and the wattage by 1 1/2. Flow is 24 hours, and is at least 35 gph per inch of width of screen [60 lph per cm], EVEN IF one sided or horizontal.

FLOATING SURFACE SCRUBBERS WITH RIBBONS: Screen size is the size of the box (Lenth X Width), and is 2-sided because the ribbons grow in 3D.

LEDs: Use half the wattage as above. 660nm (red) is best. You can mix in a little 450nm (blue) if you want.

Very rough screen made of roughed-up-like-a-cactus plastic canvas, unless floating surface, which would use gravel and strings instead.

Clean algae:

Every 7 to 21 days, or
When it's black, or
When it fills up, or
When algae lets go, or
When nutrients start to rise

[biecacka]

SantaMonica, I have 30 fish in my tank. However I have cut back feedings drastically due to water quality issues I'm having. I feed probably 2 cubes a day, but with that many fish, I want to go back to feeding more once I get the water quality issues under control. (Nitrates 75-100).

Thanks
Corey

[Jade5051]

Originally Posted by biecacka

SantaMonica, I have 30 fish in my tank. However I have cut back feedings drastically due to water quality issues I'm having. I feed probably 2 cubes a day, but with that many fish, I want to go back to feeding more once I get the water quality issues under control. (Nitrates 75-100).

Thanks
Corey

That's a lot of fish! How big is your tank?

[biecacka]

240 gallon cube. Not all big fish but none the less...30 fish.

Corey

[FullBoreReefer]

Got my lights today, 12v, modified a few things on the bucket, made a splash shield, and its up and running good, time will tell...

[SantaMonica]

Nice bucket. Those lights are nice but some have said they only use half the wattage. Maybe you can check the V and I across the LED itself.

[FullBoreReefer]

Originally Posted by SantaMonica

Nice bucket. Those lights are nice but some have said they only use half the wattage. Maybe you can check the V and I across the LED itself.

Honestly I'm not to concerned, but I too have heard the same about the claims. Plus I'd have to dig out my meter haha I figure it atleast gotta be better than the two cfl's. Worst case I add two more.

[Jade5051]

Previously, I've used Weldon 16 for my acrylic modifications/repairs. I'm going to be cutting my acrylic and making my UAS, this will be my first full fabrication. Should I use weldon 4 or 16 or something else?

[biecacka]

I used Weldon 4 for mine.

Corey

[karimwassef]

Ok. Four weeks since the last cleaning.

Export is squeezed out at 123g!





Looks like different types of algae and some cyano. I think if it sits for more that 2 weeks, it gets too thick and the growth starts to suffer somewhat. At this point, it was so thick that the sheet was twisting due to the weight (wet).

The pod andstarfish population is also getting extreme. Now there are worms and tube worms too (hard tube). I couldn't throw it out, so it went into my "export" tank. I know I'm struggling with the concept of "export" when it means trash.

Here it is cleaned:


under the scrubber, coralline seems to grow into a solid sheet in the shade



Here's the wet export in a 2 gallon bucket:



I put it in a fine net and squeeze out the liquid. I didn't know what to do with the green liquid either, so into the "export" tank it went too. I struggle with killing so much fauna...

Maybe if I create a two part control tank... one side chaeto and the other the export of the scrubber. Then put some food on the chaeto side so the pods, worms, crabs and starfish migrate to the chaeto that I can give away. Then I can throw just the microalgae away.

[biecacka]

Originally Posted by Floyd R Turbo

Ah. I would say you can get that light literally as close as you can safely put it. That's how to get the intensity out of it.

It's actually better growth than I've ever seen out of that form factor of light. I would still say though that the fixture somewhat limits the amount of algae you will be able to grow. Here's my guideline for high power LEDs



So if you follow my recommendation for a pre-made fixture of 0.5W/sq in, that would mean:

9x6 = 54, 54 * 0.5 = 27W at the wall.

Theoretically, that 45W fixture should work, the issue is the individual LEDs themselves are not very powerful, so maybe the fact that it is nearly double the "27W at the wall" is helping. My guideline above is only valid for 1W and above individually rated LEDs.

All that being said, it's obviously working on your screen on one side so I don't see why it wouldn't work on the other side also. Even if you "de rate" the fixtures by 50%, you're still in line with the guideline, so I'd say you're good

So for a 12x7 screen which is 84 sq inches....how many cubes is that? Then when you say 1 led per the equation 84/8 so that is rounded up to 11. So is that 11 fixtures per side?? Or how many watts/fixtures do you recommend? Is 12x7 maybe too large?? 30 fish in my tank so I need to feed a fair amount. If it's too large, what is a good size for say 4-5 cubes a day?

Corey

[FullBoreReefer]

Originally Posted by karimwassef

Ok. Four weeks since the last cleaning.

Export is squeezed out at 123g!

[SantaMonica]

Each 12 square inches, with proper light on each side = 1 cube. If light is on one side, then it only = 0.5 cube because the roots will die faster.