Lowest cost and easiest way to eliminate green hair, bubble, turf and slime algae

This sounds great, a good way of cleaning up your tank and getting rid of nitrates and phosphates. Question though once the algea is gone what do your snails, blennies, crabs and other algea eating critters eat? Is there a supplement you can add? Forgot to say I am new at this.
Well, most will switch to food particles on the sand. And the algae-only snails you can change for food-eating snail. But yes you can always just feed more, which is one of the advantages of a scrubber.
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 :)
What is Periphyton?

Periphyton is what turns your rocks different colors. You know... the white rocks you started with in SW, or the grey rocks (or brown wood) you started with in FW. After several months or years, the rocks become a variety of different colors and textures. Why? Because the periphyton that has grown on it is a mix of different living things, of different colors, and thicknesses. And the important part is: It is LIVING.

That's right: The colored stuff that has coated your rocks is all living organisms. Sponges, microbes, algae, cyano, biofilms, and of course coralline. After all, "peri" means "around the outside", and "phyto" means "plant". Ever slipped in a slippery puddle? That's probably periphyton that made it slippery. It's a very thin coating on the rocks, sometimes paper thin.

There is a lot of photosynthetic organisms in periphyton, and this of course means that they need light; but they need nutrients too (ammonia, nitrate, phosphate). And as you might figure, they will be on the lighted portions of the rocks. And they will grow to intercept food particles in the water, based on the water flow. Just think about how sponges orient their holes for water flow; the micro sponges in periphyton do it too but on a tiny scale.

What about under the rocks, in the dark areas? Well these periphyton don't get light, so they are primarily filter feeders. So they REALLY grow and position themselves to be able to intercept food particles. And they don't really need to fight off algae, because algae does not grow in the dark, so they have no need for anti-algae tactics like plants in the light have.

Reef studies have show that at certain depths, more of the filtering of the water comes from periphyton and benthic algae than comes from the phytoplankton which filters the deeper water. And in streams, almost all the filtering is done by periphyton. So, what you have on rocks that are "mature" or "established" is a well-developed layer of periphyton; and all the things that comes from it.

This is why mandarin fish can eat directly off the rocks of an "established" tank (tons of pods grow in the periphyton), but not on the rocks of a new tank. Or why some animals can lay their eggs on established rocks, but not new ones. Or why established tanks seem to "yo-yo" less than new ones. Even tangs can eat periphyton directly when it's thick enough. Yes periphyton can also develop on the sand, but since the sand is moved around so much, the periphyton does not get visible like it does on rocks. So thick periphyton on established rocks is your friend. And totally natural too. Keep in mind though I'm not referring to nuisance algae on rocks; I'm only referring to the very-thin layer of coloring that coats the rocks.

But what happens when you "scrape the stuff off your rocks"? Well you remove some of the periphyton, which means you remove some of your natural filter and food producer. What if you take the rocks out and scrub them? Well now you not only remove more of your natural filter and food producer, but the air is going to kill even more of the microscopic sponges in it. And what if you bleach the rocks? Well, goodbye all filtering and food producing for another year. It's an instant reduction of the natural filtering that the periphyton was providing.

However, what if you just re-arrange the rocks? Well, some of the periphyton that was in the light, now will be in the dark; so this part will die. And some of the periphyton that was in the dark will now be in the light, so it will not be able to out-compete photosynthetic growth and thus will be covered and die too. And even if the light stays the same, the direction and amount of water flow (and food particles) will change; sponges that were oriented to get food particles from one direction will now starve. So since the light and food supply is cut off, the filtering that the periphyton was providing stops almost immediately from just re-arranging.

Starvation takes a little longer. The periphyton organisms won't die immediately, since they have some energy saved up; but instead, they will wither away over several weeks. So on top of the instant reduction in filtering that you get my just moving the rocks, you get a somewhat stretched-out period of nutrients going back into the water. And after all this, it takes another long period of time for the periphyton to build up to the levels it was at before. Even changing the direction of a powerhead will affect the food particle supply in the area it used to be pointed at.

So a good idea is to try to keep everything the same. Pick your lighting, flow, layout, and try to never move or change anything. It's a different way of thinking, but you should have a stronger natural filter and food producer because of it.
Shade cloth:

All new scrubbers which use white growth surfaces should have a black cloth placed over the LEDs for the first week or two. Because the all-white interior reflects so much light, when it is new the light levels are way above the highest amount that can grow anything. Once growth starts, the white surfaces get covered with growth and the total light levels drop, and the cloth can be removed. Any cloth, stocking, or t-shirt can work; just don't melt the cloth with hot LEDs :)

This covering of the lights can be done by anyone, on any scrubber, even waterfalls. Waterfalls use plastic canvas which has more holes than material, and they are not in white compartments, so the light levels when new are not that high. But it still might help if a new screen stays completely empty or had bald spots.

The reason for a white colors, of course, is too allow more light to reach the base of the growth that does the attaching to the surfaces. As the growth gets thicker, the bottom layers will almost be in darkness, so the white surface doubles the light there by reflecting instead of absorbing the light.
SantaMonica, I recall a while ago that you had some ideas for a koi pond scrubber. You were mentioning using natural light and a bubble wand under the scrubber. Could you post a link or information for me. I need to get rolling on a scrubber to get rid of hair/string algae. Thank you.
so i am looking at all these scrubber designs and i made my own. if it works and i like it then i will make a nicer better design. here goes- piece of plastic egg crate material about 9 in by 16 in, a piece of plastic mesh screening roughed as instucted, zip tied to egg crate. a bubble curtain wand zip tied across bottom. placed flat against the back of my tank. i am using the light already in the tank to grow the algae. cost about 0 because i already had everything. so i installed it on oct 26/14, so we see if this does any thing ang how long it takes to green up.
Would be nice to see pics. The screen probably will work, but if you are using the display light, you will need to get a much brights light placed next to the screen
yup, i do believe you are right, but i dont have a sump so i have to put it in my tank. i am going to let it run for a couple wks and see what happens
Scrubbers compared to refugiums

If you are starting a new tank, then the obvious difference is that a scrubber gives you the option of not having a fuge at all because an upflow scrubber can be placed on top of, in, or behind, the display. There are other uses for a sump/fuge of course, but we'll only cover the filtration concerns here.

A not-so-obvious difference is that a scrubber, if run together with a fuge with macros, will kill the macros even though the macros are much larger. This is because the scrubber thinks the macros are nuisance algae. Some people do run both together without killing the macros, but this is just because their scrubber is not strong enough, and actually the macros might even be slowing down the scrubber because the scrubber thinks it has to remove the macros, along with the nutrients in the water and the nuisance algae in the display. However if this works for them, good.

But assuming you have to decide on either a sump/fuge or a scrubber (not both)...

o Filtration with algae is proportional photosynthesis, which is proportional to Light X Air Water Turbulence Flow X Attachment. Meaning, stronger light grows more algae; stronger air/water interface turbulence grows more algae; and stronger attachment lets more algae grow without it detaching and floating away. A scrubber is thus designed to maximize Light, Flow, and Attachment.

o The main problem with macros in a refugium is the self-shading that the macros do. Any part of the macro which is not directly in front of the light at any moment is not filtering. And any macro inside of a "ball" of macro (like chaeto) is self-shaded all the time. Only the surface macro that is directly in front of the light is doing any real filtering. A scrubber is designed to have all the algae in front of the light at all times. Rotating the macro does not solve the problem, because the time that the macro is rotated away from the light is time that the macro is not filtering. This is why it takes a much larger size of chaeto to do the same filtering as a scrubber.

o Self-flow-blocking is another problem of macros in a refugium, for the same reason as light-blocking. And the thicker the "ball" of macro, the worse the flow-blocking.

o Particle trapping is another result of a ball of macro. These particles need to cycle back around to feed the corals, but instead they get trapped in the macro and they rot, and in doing so they block even more flow and light.

o With a scrubber, there is very little water standing in the way of the light. Also, the light is (or should be) very close to the scrubber... 4 inches (10cm) or less. The power of light varies with the inverse square of the distance, so going from 8" to 4" actually gives you 4X the power, not 2X. And the nutrient removal power of algae is proportional to the power of the light, because it's the photosynthesis that is doing the filtering.

o Rapid flow across the algae in a scrubber gives more delivery of nutrients, compared to the slow moving water in a fuge. Filtering is proportion to nutrient flow.

o The turbulence of water moving over the sections of algae in a scrubber help to remove the boundary layer of water around the algae. This boundary layer slows the transfer of metabolites in and out of the algae. There is no turbulence in a fuge (if there were, you'd have waves and bubbles). The interface between the air and water is what provides the most turbulence and boundary layer removal; there is no air/water interface in macros.

o Scrubbers do not let food particles settle like a refugium does; most particles flow right out of the scrubber.

o Scrubbers do not (if cleaned properly) release algal strands into display, like chaeto does.

o Scrubbers do not go sexual, like caulerpa can.

o Scrubbers do grow lots of pods; more than was previously thought, especially if not cleaned with freshwater.

o Scrubber don't, obviously, provide a place for snails and crabs, etc.

However, if you already have a sump with an empty compartment, and you don't mind using all of it and putting a light over it, then maybe it's easier and cheaper to try macros first.
.thank you. this gave me a much better understanding of how an algae scrubber works. i am setting up a new tank with over flows and a sump with a refugium in it. i think i am going to redesign and get my algae scrubber in there too. the algae scrubber will be much more efficient because of your article
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What are the dimensions on the HOG.5. If I cleared out the center section of my sump (the refugium part) maybe it could fit there depending on how much room is needed. So I guess the question should be how wide is the light when installed. That section just happens to be right where the center brace is on the stand.
Cleaning Off Slime On New Scrubbers

When scrubbers are new, they will almost always first develop a slimey first layer of growth. This is because diatoms and dino's, which make up most of the slime, are the quickest to be able to "colonize" a new surface, sort of like weeds in a new garden.

This slime layer will not get any thicker, however, because slime cannot attach well (it has no "roots") to the growth surfaces of the scrubber, and thus will get washed away when it gets thick, Also, it prevents green hair algae from attaching because of the slippery texture of the slime.

So when your scrubber is new, be sure to take it to the sink and use a toothbrush to clean all the slime off of the growth surfaces so you can see all white surfaces again. You could clean it while still in your tank if you don't mind the slime particles floating around, but most people would probably do better to take it to the sink (or outside; slime makes great fertilizer). Slime, especially when dark or black, is also an indicator that you can use more watts or hours of light.

Once you have cleaned off the slime for one or more growth periods, you should start seeing green hair algae take hold.