Algae Scrubber Basics

[Johnb123]

would something like this work well?

[karimwassef]

That's similar to my overflow scrubber. Sits in my end to end weir

[Johnb123]

^cool! i have a 80 gallon aio system so i could only fit the small size which is 7cm x 30cm is it even worth it for me? it's pretty much that in the pic i posted except for a much larger tank

[Johnb123]

or should i install a bigger upflow ats in one of my aio compartments in the back? i didn't read through all 300 pages but i did notice some comments on upflow ats not being as good.. is this still true?

[Spar]

Originally Posted by Jade5051

Where did you get parts and how much did this cost you?

From Rapid LED. 2 units totaled $300. I did 20 led's per unit, 2 drivers per unit.

You can get cheaper and better fit heat sinks from http://www.heatsinkusa.com/ (Rapid LED is who recommended that place), but I kept it simple and got the 6x12s from them also.

[SantaMonica]

comments on upflow ats not being as good.. is this still true

If you ask the two people here that make waterfalls, they will say yes

[karimwassef]

let me ask the questions differently. If you had unlimited space and resources $, what scrubber would you recommend?

[jason2459]

Originally Posted by SantaMonica

If you ask the two people here that make waterfalls, they will say yes

Have you read this thread?

[SantaMonica]

No one has unlimited. If you did you would build a real reef and just watch it.

[Jade5051]

@SantaMonica, do UAS require bubbles or could I just use a powerhead to move water? Do the bubble have an advantage or benefit over just moving water with a powerhead?

[Johnb123]

Originally Posted by Jade5051

@SantaMonica, do UAS require bubbles or could I just use a powerhead to move water? Do the bubble have an advantage or benefit over just moving water with a powerhead?

yes it does as the bubbles create air and gas exchange for the algae to grow more effectively

[Johnb123]

Originally Posted by karimwassef

That's similar to my overflow scrubber. Sits in my end to end weir

how effective was this for you? have you noticed a great reduction in nitrates and phosphates?

[karimwassef]

I don't measure nitrates and phosphates. They're always below my measurement because I have algae or macroalgae. They're constantly getting bound up in their tissues.

I see the results in polyp expansion and coral growth rate that's improved. I can also feed more generously without compromising my water quality.

[karimwassef]

You have unlimited space for the ATS, but very limited space for the reef

Now what?

[SantaMonica]

do UAS require bubbles

Yes

[biecacka]

So Floyd, I'm thinking of installing a water flow type in my system. It will be similar to yours in the enclosed box, above my sump, draining back to my sump and fed by my return pump. Lit on both sides probably with CFL until I can find some prefabbed LEDs (any suggestions). I have a 240 gallon tank with 30 fish. Nitrates about 75 not. Cut feeding down to help,with reduction of nitrates. But need to get feeding back up so my fish can eat.


Karimwassef, how is your overflow box scrubber working, I might consider that route as well.

Corey

[karimwassef]

It's going great. I expected it to be a good backup to my macro refugium, but it's taken off with a lot more mass than I expected.

I now have no algae at all in the DT to the point that my tangs are starving and near ravenous. I doubled my nori feeding and then doubled again and it's still not enough. I had assembled a small army of tangs to keep the algae under control and they were balanced with my feeding. Now I have to actively feed vegetable matter. I lost a blenny to starvation since it couldn't compete with the army of aggressive tangs.

I worked this weekend but I was hoping to clean it. I'll get to it next weekend and I'll take more pics. The growth is dark green and very lush. Unfortunately, it's also getting heavily colonized with starfish and pods exacerbating my dilemma of how to avoid killing them during export.

[biecacka]

Here is my concern with the overflow scrubber*** my overflow is only about 24 inches long. would that suffice do you think?


*** = trademarked that name!!!!

corey

[karimwassef]

The active area in my overflow is about 5'. I have more space, but that's the area that gets enough light and flow. Also, it depends on how deep your overflow is. Mine is only about 6" deep and 4" thick, so I just lay it flat (4" x 5'). If you have more depth or thickness, use them.

It costs almost nothing - try it. If you're not getting enough light, add a dedicated light over it.

I like to try easy first and then only add complexity when simple doesn't work well enough.

[SantaMonica]

Yes the horizontal river versions are nice if you have the room.

[biecacka]

So I have about 24inches wide and it's 24 inches deep. But the water sits in the overflow as its a durso type drain. So I'm not even sure if it will work because the top of the drains are above the water line.

Corey

[biecacka]

What size screen is recommended for me. 30 fish in my 240. Would like to get back to 4 cubes or so daily, plus nori. Rig now nitrates are 75-100. Am dosing vodka/vinegar currently. Starting my third week of it.

Corey

[karimwassef]

Take a pic of your overflow. Every overflow has a lip, trough and lines. I have 2" PVC elbows in mine.

[Floyd R Turbo]

Originally Posted by SantaMonica

If you ask the two people here that make waterfalls, they will say yes

Originally Posted by jason2459

Have you read this thread?

Originally Posted by Floyd R Turbo

This is the answer to "why is a UAS better than a waterfall" not his question which was

this is a better answer:

Here is my pro and con list:


Waterfall (includes a slanted scrubber, and for the most part, a horizontal/raceway scrubber)

At minimum, you need a slot pipe or some other method to deliver water up so that if cascades down the screen, a roughed up piece of plastic canvas (Darice #7 mesh), a pump, and lights (usually on both sides) and a timer (for lights, water flow is 24/7)

Installation has to be above water or tank. Screen can be in sump below the "power off" water level, but lights cannot. So you need to support the slot pipe somehow, and it should be level. Difficult to incorporate into a non-sump system (but not totally impossible)

Since it can easily be 2 sided, you get double the growth area compared to a UAS of the same LxW screen (theoretically).

The water flow requirements usually dictate the use of a pump, because the flow rate is 35 GPH/in of screen width, so rates like 200, 300, 400 GPH actual flow across the screen (after head loss) are typical.

A waterfall scrubber creates a thin layer of high-speed laminar flow that allows nutrients to reach the algae. The laminar flow is what breaks the "boundary layer", which is the term used to describe the area that it microscopically close to the algal cells (flow goes to zero as you get closer to the algae)

A waterfall scrubber can form "streamer" if you don't protect the slot/screen junction. A 'streamer' is my term for when algae grows up toward the slot/screen junction and causes a pressurized point where water can spray sideways, literally horizontally, and get out of your sump. Adding Saran wrap over this area usually does a pretty good job of preventing the streamer, but not the growth. A blackout material does both.

Water can also "creep" along the pipe, adding a piece of airline tubing with a zip tie snaked through it and cinched around the pipe helps to prevent this, as does making sure the pipe is level (or placing it wholly within the footprint of the sump)

Water pressure prevents algae from actually clogging the slot/screen junction. Supplying the screen directly from the overflow will work fine because of this, but anything that goes down the overflow pipe (anemone, snail, etc) can block the flow, so you would need an open-end bypass unless you have a secondary overflow path that can handle the full return pump flow (so that you don't overflow your tank). Dedicated pump eliminates this, as does a return pump tap.

An open-screen scrubber cannot overflow. See above other issues

A closed-box scrubber can overflow, if not constructed correctly and (especially) if not maintained properly. Adding a secondary drain can help prevent an overflow (it will buy you time, essentially). Adding a removable/false bottom to prevent algae growth (and light) from having a direct path to the drain will help prevent the drain from clogging. But it basically comes down to making sure you maintain it or at least check it regularly, as it is not typical for a closed box scrubber to suddenly clog and overflow rapidly (not in my experience). This is because a closed-box scrubber tends to cause water to "build up" inside the box and suspend the algae so that it doesn't detached due to it's own weight, so the thing that would cause an overflow is too much algae growth - and since algae growth is gradual, not sudden, you get the point. As water rises, so does pressure, so a reduced drain flow will self-adjust when the water level above it increases. This of course will only work until the water level reaches the top of the box, but that comes down to monitoring the scrubber and knowing it's typical growth cycle so that you know when to clean it.

An open-screen scrubber can cause salt spray and salt creep on the lights, which may or may not cause issues with lighting, or generally annoying salt creep.

During a power outage, where the lights and pump shut off, an open-screen waterfall scrubber can dry out, but it takes several hours until damage starts taking place - but this depends on the point in the growth cycle, if you have a full screen, maybe 6 hours; a freshly cleaned screen might start to dry out in an hour. A closed-box scrubber will usually last a bit longer.

If a water pump goes out, and the lights stay on, the screen will dry out much faster

A waterfall scrubber can smell a bit during the first few weeks as the initial maturing happens, but this goes away as normal growth kicks in. After that, you would typically only smell the scrubber when you shut off the water flow prior to cleaning. And it doesn't gag you like skimmate smell does


UAS:

At minimum: need a substrate (can be canvas, but this is not ideal for a UAS - crushed quartz bonded to a solid panel has proven to be better), an air pump and air stone/bubbler, and lighting (usually only feasible to light one side)

Since it is usually only feasible to light one side, capacity is reduced when compared to a 2-sided waterfall (reverse of above)

When installed under water line, usually pretty easy to install by just dropping in the tank. This makes it adaptable to just about any tank, and makes it especially useful in biocubes or other sumpless systems.

Requires an air pump to operate, as the bubbles provide turbulence and water movement. The air bubbles are what provides the mechanism to break the boundary layer in a UAS.

Air pumps can be noisy by themselves and can vibrate up against something even if they are quiet, but there are ones that are pretty quiet and high-volume at the same time, so this is more about selection.

The water movement provided by air bubbles alone is much lower than that of a waterfall scrubber. So you get less turnover. If the UAS is a "closed" system (not just a screen strapped to an airstone, dropped in the sump) the constant motion provided by the air bubbles means that the water that is inside the box is recirculated and there is more contact time, so one could make the argument that the water is filtered to a higher level before it leaves the box. In contrast, an "open" UAS might have more inherent turnover by way of normal circulation, with the bubble providing randomness, but the flow might actually carry the bubbles away from the algal mat, defeating the purpose of the bubbles. So this comes down to construction.

Bubbles pop and this can cause salt creep. For an open scrubber, this can be an issue but it can also be remedied in various ways. For a closed scrubber, this can be remedied by placement of the unit such that the bubbles breach the surface within the unit.

On a power outage, the algae stays submerged so it can stay alive for days without too much die-off.

On an air pump failure in a closed UAS, with lights still running, the algae will eventually reach a point of photosaturation as there is no water movement and it will start to turn white and die.

A UAS will generally not smell at all until you take it out of the water to clean it


That's what I can think of at this point.

Generally, a waterfall scrubber has a lot more components and issues to account for related to construction and maintenance, but once you get that down, it's pretty much on autopilot.

The UAS is much simpler to build and more useful for smaller systems where you are not likely to feed a ton. But IMHO they don't scale up well to very large systems.

I thought that was pretty well thought out...I guess I should have just posted "yes" because apparently, that's what all this above means.

[Floyd R Turbo]

Sorry for my absence, I was on the vacation from h--l. Well I wouldn't say that, I was on a vacation that went badly for several reasons, including having to admin our 19 yr old daughter to the hospital for acute pneumonia and her never setting foot in Universal Studios and doing all the Harry Potter stuff that she really wanted to do (whole week in bed). Weather sucked but not as bad is it was in Iowa so I can't complain too much. No scrubbers overflowed while I was gone so that it good.