Algae Scrubber Basics
- Thread starter srusso
- Start date
Floyd R Turbo
Either busy or sleeping
Let me put it another way. Does a higher flow rate have an upper limit of benefit?
my very first scrubber was actually running at about 20 GPH/in of width, limited by pump and return plumbing capacity. It grew very well. Future versions which were pump fed and had higher flow rates also did just fine, hard to recall if there was that much of a growth difference. I'd have to go back and look.
Flash forward, I've taken feedback from many people running the same size unit at various flow rates. Almost without fail, those that run very high flow rates have huge amounts of growth.
So, if considering a waterfall, if you get a ton of growth and push a lot of flow at the same time, I would imagine that as the algae mat expands thicker and thicker that the flow to the lower layer decreases, and the flow to the intermediate layers decreases as well (but not as much). So you would have different levels of flow within a growth mat that would result in a variation of characteristics at each level.
So, with a thicker mat, you would have a high flow, high light area (surface) and a low flow, reduced light area (screen level). Are you saying that these both serve a different purpose?
my very first scrubber was actually running at about 20 GPH/in of width, limited by pump and return plumbing capacity. It grew very well. Future versions which were pump fed and had higher flow rates also did just fine, hard to recall if there was that much of a growth difference. I'd have to go back and look.
Flash forward, I've taken feedback from many people running the same size unit at various flow rates. Almost without fail, those that run very high flow rates have huge amounts of growth.
So, if considering a waterfall, if you get a ton of growth and push a lot of flow at the same time, I would imagine that as the algae mat expands thicker and thicker that the flow to the lower layer decreases, and the flow to the intermediate layers decreases as well (but not as much). So you would have different levels of flow within a growth mat that would result in a variation of characteristics at each level.
So, with a thicker mat, you would have a high flow, high light area (surface) and a low flow, reduced light area (screen level). Are you saying that these both serve a different purpose?
Floyd R Turbo
Either busy or sleeping
Well don't leave us hanging, explain!
Floyd R Turbo
Either busy or sleeping
With either waterfall or up flow you want them closer than 6-7" ideally. Depends on light source also.
SantaMonica
Well-known member
Fun weekend reading:
First waterfall post:
http://www.reefcentral.com/forums/showthread.php?t=1424843
----------------------------------------------------
Nutrient Export:
What do all algae (and cyano too) need to survive? Nutrients. What are nutrients? Ammonia/ammonium, nitrite, nitrate, phosphate and urea are the major ones. Which ones cause most of the algae in your tank? These same ones. Why can't you just remove these nutrients and eliminate all the algae in your tank? Because these nutrients are the result of the animals you keep.
So how do your animals "make" these nutrients? Well a large part the nutrients come from pee (urea). Pee is very high in urea and ammonia, and these are a favorite food of algae and some bacteria. This is why your glass will always need cleaning; because the pee hits the glass before anything else, and algae on the glass consume the ammonia and urea immediately (using photosynthesis) and grow more. In the ocean and lakes, phytoplankton consume the ammonia and urea in open water, and seaweed consume it in shallow areas, but in a tank you don't have enough space or water volume for this, and, your other filters or animals often remove or kill the phytoplankton or seaweed anyway. So, the nutrients stay in your tank.
Then the ammonia/ammonium hits your rocks, and the periphyton on them consumes more ammonia and urea. Periphyton is both algae and animals, and is the reason your rocks change color after a few weeks. Then the ammonia goes inside the rock, or hits your sand, and bacteria there convert it into nitrite and nitrate. However, the nutrients are still in your tank.
Also let's not forget phosphate, which comes from solid organic food particles. When these particles are eaten by microbes and clean up crew, the organic phosphorus in them is converted into phosphate. However, the nutrients are still in your tank.
So whenever you have algae "problems", you simply have not exported enough nutrients compared to how much you have been feeding (note: live rock can absorb phosphate for up to a year, making it seem like there was never a problem. Then, there is a problem).
So just increase your nutrient exports. You could also reduce feeding, and this has the same effect, but it's certainly not fun when you want to feed your animals
----------------------------------------------------
Scrubber sizing guidelines:
Scrubbers are sized according to feeding. Nutrients "in" (feeding) must equal nutrients "out" (scrubber growth), no matter how many gallons or liters you have. 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
First waterfall post:
http://www.reefcentral.com/forums/showthread.php?t=1424843
----------------------------------------------------
Nutrient Export:
What do all algae (and cyano too) need to survive? Nutrients. What are nutrients? Ammonia/ammonium, nitrite, nitrate, phosphate and urea are the major ones. Which ones cause most of the algae in your tank? These same ones. Why can't you just remove these nutrients and eliminate all the algae in your tank? Because these nutrients are the result of the animals you keep.
So how do your animals "make" these nutrients? Well a large part the nutrients come from pee (urea). Pee is very high in urea and ammonia, and these are a favorite food of algae and some bacteria. This is why your glass will always need cleaning; because the pee hits the glass before anything else, and algae on the glass consume the ammonia and urea immediately (using photosynthesis) and grow more. In the ocean and lakes, phytoplankton consume the ammonia and urea in open water, and seaweed consume it in shallow areas, but in a tank you don't have enough space or water volume for this, and, your other filters or animals often remove or kill the phytoplankton or seaweed anyway. So, the nutrients stay in your tank.
Then the ammonia/ammonium hits your rocks, and the periphyton on them consumes more ammonia and urea. Periphyton is both algae and animals, and is the reason your rocks change color after a few weeks. Then the ammonia goes inside the rock, or hits your sand, and bacteria there convert it into nitrite and nitrate. However, the nutrients are still in your tank.
Also let's not forget phosphate, which comes from solid organic food particles. When these particles are eaten by microbes and clean up crew, the organic phosphorus in them is converted into phosphate. However, the nutrients are still in your tank.
So whenever you have algae "problems", you simply have not exported enough nutrients compared to how much you have been feeding (note: live rock can absorb phosphate for up to a year, making it seem like there was never a problem. Then, there is a problem).
So just increase your nutrient exports. You could also reduce feeding, and this has the same effect, but it's certainly not fun when you want to feed your animals
----------------------------------------------------
Scrubber sizing guidelines:
Scrubbers are sized according to feeding. Nutrients "in" (feeding) must equal nutrients "out" (scrubber growth), no matter how many gallons or liters you have. 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
Floyd R Turbo
Either busy or sleeping
My recommendation for LEDs differs, and is based on coverage not wattage. This is due to the fact that if talking wattage, it can get confusing because you can vary the drive current. Also 660nm "3W" Deep Reds typically have a 700mA maximum drive current and a 2.0-2.2v drop, so for anyone good at math, that's 1.5W not 3W - but they still call them "3W"...basically because of marketing.
So, with that being said, my recommendation is:
Standard light level: One 3W 600nm Deep Red on each side of every 8 sq in of screen.
High-intensity level: One 3W 600nm Deep Red on each side of every 4 sq in of screen.
Blue light supplementation: This should be done very conservatively. You don't need much. 440-455nm Royal Blue LEDs should be used, but Deep Violets can be used also. 1W versions can be used. 3W should be run at low current - 350-400mA maximum. For the 3W LEDs running on the same driver as the reds, you can wire them in parallel so they act like a current divider.
Blue placement should be about one half-power blue for every 3 Deep Reds, maximum. You could even go 6:1 or 8:1.
Distance from LEDs to screen should be about 2"-3". If running high-intensity on a new (bare) screen, either run them at 350mA or use a diffuser until the screen is mature.
Initial photoperiod should be no more than 9 hours/day. If screen stays pretty much white after 1 week, reduce photoperiod or split up into 2 or more sections with a 1 hour dark period in between. This is typically necessary for oversized and underfed screens (4 hours/day is not atypical on low fed setups)
A few interesting facts about this particular thread:
Over 5800 replies and over 525,000 views.
Within the "Advanced Topics" subforum, this thread now surpasses the next 2 closest threads which are:
DSB in a bucket threads which have a combined total of 1700+ posts and 385,000+ views
Solatube threads which have a combined total of 1200+ posts and 370,000+ views
Not too shabby.
So, with that being said, my recommendation is:
Standard light level: One 3W 600nm Deep Red on each side of every 8 sq in of screen.
High-intensity level: One 3W 600nm Deep Red on each side of every 4 sq in of screen.
Blue light supplementation: This should be done very conservatively. You don't need much. 440-455nm Royal Blue LEDs should be used, but Deep Violets can be used also. 1W versions can be used. 3W should be run at low current - 350-400mA maximum. For the 3W LEDs running on the same driver as the reds, you can wire them in parallel so they act like a current divider.
Blue placement should be about one half-power blue for every 3 Deep Reds, maximum. You could even go 6:1 or 8:1.
Distance from LEDs to screen should be about 2"-3". If running high-intensity on a new (bare) screen, either run them at 350mA or use a diffuser until the screen is mature.
Initial photoperiod should be no more than 9 hours/day. If screen stays pretty much white after 1 week, reduce photoperiod or split up into 2 or more sections with a 1 hour dark period in between. This is typically necessary for oversized and underfed screens (4 hours/day is not atypical on low fed setups)
A few interesting facts about this particular thread:
Over 5800 replies and over 525,000 views.
Within the "Advanced Topics" subforum, this thread now surpasses the next 2 closest threads which are:
DSB in a bucket threads which have a combined total of 1700+ posts and 385,000+ views
Solatube threads which have a combined total of 1200+ posts and 370,000+ views
Not too shabby.
Brummie
Member
Right Bud, here's the article I was talking about with regard to changes in the Redox Potential in thick algae beds;
http://www.soest.hawaii.edu/oceanography/PhD/2012-Murphy.pdf
Having trouble locating the academic reports on hydrogen peroxide production, so heres a wiki excerpt;
http://www.soest.hawaii.edu/oceanography/PhD/2012-Murphy.pdf
Having trouble locating the academic reports on hydrogen peroxide production, so heres a wiki excerpt;
Brummie
Member
Just to add a tit bit to SM's post, I'm pretty sure most ammonia produced by fish is actually a constant process which transfers across the fish gills through an osmotic process which relies on extremely low ammonia in the water column. I'm struggling to believe that ammonia or nitrate will ever be limiting to algae growth in a display (housing fish at least) and that the reduction in display algae is due to other factors, or aggravating factors.
crn005
New member
So here's the update on my screen. I bumped it from 9 to 11 hours of exposure on my last post (3/23) and this is what happened. I'll attach a picture below. I cleaned the screen on 4/7 and pumped the exposure from 11 to 13. If I'm not mistaken, it has darkened up and needs more light, right?
Just for reference, here's what it was like two and a half weeks ago on 3/23.
Just for reference, here's what it was like two and a half weeks ago on 3/23.
Floyd R Turbo
Either busy or sleeping
You might just "swipe" off the top layer of growth, and leave whatever does not easily come off in place. As you know, you eventually want growth to fill in the holes, and grow thick enough so that you cannot see the mesh pattern by the time you need to clean it. Until you get to that point, you will not be getting any kind of dying resulting from shading - far from it. Under LEDs, I barely get any dead areas even after 14 days of growth and a 0.5"-1" thick mat.
Floyd R Turbo
Either busy or sleeping
I would continue to let it grow and clean as you described every 7-10, maybe 14 days. You might scrape like 1/2 of it a bit more vigorously at the next cleaning
I am thinking about purchasing 2 of the 30 watt multi chip lights. Tank is around 120 gallons. I currently feed 1 cube per day but I would like to increase to 2 cubes. Screen size suggestions? Is it better for the screen to wider or taller? I have some flexibility.
Floyd R Turbo
Either busy or sleeping
I would go with a minimum of a 24 sq in screen, and depending on the way you set up the light fixtures (are these stock fixtures or DIY?) then maybe a square screen so 5x5 or 6x6.
Wider vs taller: taller screen means lower flow (overall) and more vertical contact time. Wider screen means more flow and less contact time. It's a bit of a wash, really. I would just size it according to your space available and your form factor of your light fixture. Even light coverage is more important. With multichips, you will probably want to use a diffuser or else you will get a "hotspot" in the middle of the screen. This is actually photosaturation=too much light. If you back off the LEDs too much, then you might not get enough light. Multichips are like that it seems
Wider vs taller: taller screen means lower flow (overall) and more vertical contact time. Wider screen means more flow and less contact time. It's a bit of a wash, really. I would just size it according to your space available and your form factor of your light fixture. Even light coverage is more important. With multichips, you will probably want to use a diffuser or else you will get a "hotspot" in the middle of the screen. This is actually photosaturation=too much light. If you back off the LEDs too much, then you might not get enough light. Multichips are like that it seems
The light from this post. 30 watt multi
