Algae Scrubber Basics

[PowermanKW]

PowermanKW
Have you seen PaulB's trough in post #138?
srusso describes a bucket style dumper in #94, my understanding is that an air / water interface is needed for best efficiency.

Not lately, but I have seen it before. Air/water is good... that was the sort of thing I didn't think about. My thought was to have an overflow that left a certain amount of water in... so as not to drain dry with a pump off, but with this line of thinking I could just go shallower than what I was thinking.

Also, the trough thing would be long instead of wide. So I thought as nutrients were stripped that the water would not support growth at the end. But to clean it I would just clean one end or the other when needed and the water would still be scrubbed.

redneckgearhead Unfortunately I am tankless. Selling the house and prioities... but I have ideas for what I want to do in the future... alaways been a big fan of good skimmers, but thought a more "natural" approach would be cool. To have a minimal display, but a tub of LR and DSB... and algae for nutrient export... that perhaps if I could keep nutrients low that way, I would not have to skim and the food chain would be more robust. Don't really know, but I'm interested. Not my thinking that a ATS is "better" than a skimmer... but that how much bio filter (algae, DSB, LR...) would it take to keep a 180g sized reef low nutrient?

 

[TheFishMan65]

Powerman, the problem is the boundary layer between the water and algae. From my understanding horizontal scrubbers need the tidal action of a dump bucket. Otherwise the water near the algae stays stagnant. This is one of the reasons the vertical ones need so much flow (to break up this boundary layer).

 

[PowermanKW]

Powerman, the problem is the boundary layer between the water and algae. From my understanding horizontal scrubbers need the tidal action of a dump bucket. Otherwise the water near the algae stays stagnant. This is one of the reasons the vertical ones need so much flow (to break up this boundary layer).

I see what you are saying... that regarless of how it looks, water would just be flowing over the top and within the algae mat not much would be changing. If it would not work efficiently enough, then I woul dbe back to a traditional ATS... or just a very well lit traditional fuge with macro. But since more traditional ATS are much more efficient for the reasons given, then it would seem that a horizontal would not be any less efficient than a fuge with macro. Perhaps an inbetween a ATS and a fuge?

 

[TheFishMan65]

then it would seem that a horizontal would not be any less efficient than a fuge with macro

I think that depends on the algae. The horizontal scrubber has the benefit of more light. But a fuge will allow more surface exchange for macros. I think the vertical ATS is probably best, but maybe one of the experts will no more.

 

[tyler3276]

where can i get some of that screen at

 

[JeffBoyRD]

Most any Arts/Crafts stores like Michael's, Hobby Lobby, etc.

 

[XSiVE]

So I took a pic of my screen last night just before I cleaned it (for the 3rd time in approximately the first 2 weeks) I should have cleaned it a little more often, but does this look pretty typical for how it should be over the first two weeks? The hot spot there was getting a little low flow until I re-cut my slot tube and also moved the lights back a little.

 

[TheFishMan65]

Xsive, great idea. Floyd could you add some pictures of the expected growth for the first few weeks? You may have to collect them from some of the submitted ones )unlesss you are starting a scrubber), but I think it would really help. Also maybe some error pictres, not enough light, too much, too many pods, and whatever else I missed.

 

[Floyd R Turbo]

Yeah I've been meaning to get some of that stuff together, it's on my list of a million things to do when the wife and kids and work don't take up all my time.

xsive, what is your flow in GPH/in, tank specs, water parameters, screen dims, light specs & reflector, etc

 

[TheHoove]

So for those that have done LED, what ones have worked best? I have a lpc-60-1050 driver left over from my build for my display tank. I may experiment with LED.

 

[XSiVE]

Yeah I've been meaning to get some of that stuff together, it's on my list of a million things to do when the wife and kids and work don't take up all my time.

xsive, what is your flow in GPH/in, tank specs, water parameters, screen dims, light specs & reflector, etc

Display is 120gal, screen is about 12" wide by about 12" tall (outside of the water line that you can see in the pic), lighting is currently 3x 23W 2700k CFL's with 8.5" reflectors, two on one side one on the other which is all I can fit with the current config.

I have the scrubber actually running off the overflow of my 10g frag tank which is plumbed into the same sump as the display. I calculated the GPH/inch at about 25 which I know is a little lower than typical but since it runs off the overflow it seems to surge a little bit which seems to make up for the slightly lower flow rate.

Water parameters for N and P, im not sure as I recently threw away my test reagents as they were well beyond expired. I know it's working a little as the GHA in my display is starting to brown and die in places.

 

[Floyd R Turbo]

I am going to be running an experiment to try and determine what works best. I currently have 2 custom fixtures being made and will be able to use those to test almost a dozen combinations of red, deep red, blue, and royal blue.

For now, if you're going to DIY it, most have had good results from 630nm red and a few have said that 660nm Deep Red works great.

 

[Floyd R Turbo]

Display is 120gal, screen is about 12" wide by about 12" tall (outside of the water line that you can see in the pic), lighting is currently 3x 23W 2700k CFL's with 8.5" reflectors, two on one side one on the other which is all I can fit with the current config.

I have the scrubber actually running off the overflow of my 10g frag tank which is plumbed into the same sump as the display. I calculated the GPH/inch at about 25 which I know is a little lower than typical but since it runs off the overflow it seems to surge a little bit which seems to make up for the slightly lower flow rate.

Light is a little low and flow is too, but as long as your nuisance algae is not a problem and your N and P are low, who cares?

Water parameters for N and P, im not sure as I recently threw away my test reagents as they were well beyond expired. I know it's working a little as the GHA in my display is starting to brown and die in places.

That's the key. If it works, you can see the results. Even if you don't build it 100% right, it will still do something, it may no be able to handle a full bioload and heavy feeding, and it may not be able to battle a bad cyano problem, but it's still very effective.

 

[Rabidgoose]

XSIVE;

Can you point me toward pictures of your scrubber or post some if their are none. We have similar size requirements it seems.

thanks........chuck

 

[TheHoove]

I am going to be running an experiment to try and determine what works best. I currently have 2 custom fixtures being made and will be able to use those to test almost a dozen combinations of red, deep red, blue, and royal blue.

For now, if you're going to DIY it, most have had good results from 630nm red and a few have said that 660nm Deep Red works great.

Its interesting, I have a couple spots of hair algae still in my tank on the return and in the overflow, and it hasent slowed down any since switching from my old pc lights to my leds. My leds are 2r royal blue, 14 neutral white, 5 cool white, 5blue. so im guessing most combination would grown the algae. But not sure the most efficient. PaulB added a led strip over his algae trough. wonder how his growth is doing?

 

[PowermanKW]

Horizontal scrubbers are not as effective and really only work well if you have a surge type of setup. Horizontal screens that are constantly submerged do not work well at all. Also you need 1.5W per square inch, minimum, and must have reflectors. You have 36W over 98 square inches which is 0.36 W/sq in.

Horizontal surge/dump scrubbers have a tendency to grow red turf algae, which is not as effective as vertical waterfall style scrubbers. This is why I don't recommend horizontal scrubbers - they're fraught with the problems of the past.

So is there anyother problems with horizontal scrubbers besides the ones listed. Do you have some examples of ones that didn't work out well?

 

[Floyd R Turbo]

The original dump-bucket style scrubber has moving parts, makes noise, can splash, when the turf is exposed is smells, they're bulky, large, and expensive. You can buy them from Inland Aquatics and they pay a royalty to Adey I believe (one of the reasons they are expensive) so you can't really get them made anywhere else to my knowledge. Very early on in this thread there is a nice example of one someone built that makes a nice surge in their tank though, so they're not completely horrible, just much more complex and difficult to build.

If you don't go with a dump-style, then it's easier, but you still have a lot of horizontal space requirement. The screen needs to be double the size that it needs to be for a comparable vertical scrubber, so if you have a 100g tank you would normally need a double-lit vertical screen 100 sq in (L x W), for one lit on only one side it would need to be 200 sq in (L x W), and for horizontal you need 400 sq in (L x W). Then it needs 50% more light because you need to spread it out more to cover the area, and then you're still running it at a lower watt/sq in.

Horizontal non-dumping screens also have a tendency to 'channel', where the algae will grow thick and divert water around it, leaving pockets of stagnant water that will have nearly zero flow and no boundary layer flow to speak of, which all but eliminates filtration in those areas. Slanted screens have a little less of this, but it is still there.

These are all the issue of the past that really made algae scrubbers ineffective. That and poor lighting, that's a big one.

So if you're going to make a horizontal scrubber, the key is to at least try to incorporate some kind of surge device, perhaps a constant low flow to keep the algae covered and help keep the smell down and a surge box to dump at regular intervals, and over-light the snot out of it.

 

[terahz]

Ok, so after reading the summary, you guys are saying that all I need on my 40B is a 6"x7" double sided screen? A couple of red and a blue CREEs on each side and call it a day? That sounds too simple

On LEDs: the green algae in my tank seem to have no trouble growing on CW/RB mix, just saying

You guys should really push for a reefcentral WIKI! going through hundreds of pages of posts is a pita.

 

[Floyd R Turbo]

Ok, so after reading the summary, you guys are saying that all I need on my 40B is a 6"x7" double sided screen? A couple of red and a blue CREEs on each side and call it a day? That sounds too simple

On LEDs: the green algae in my tank seem to have no trouble growing on CW/RB mix, just saying

You guys should really push for a reefcentral WIKI! going through hundreds of pages of posts is a pita.

You want heavy red and hardly any blue, if any at all. One LED build used RB/WW and grew almost nothing, then switched to all Deep Red and he has to clean every 3 days. Trust my when I say, do not use CW, NW or RB on a scrubber. You need lots and lots of red.

The jury is still out on what red works best and what blue also (because it's never really been bench tested)

The other issue with LEDs is spotty growth since it's difficult to spread 3W crees, so you're right it's just not that simple.

 

[terahz]

You want heavy red and hardly any blue, if any at all. One LED build used RB/WW and grew almost nothing, then switched to all Deep Red and he has to clean every 3 days. Trust my when I say, do not use CW, NW or RB on a scrubber. You need lots and lots of red.

The jury is still out on what red works best and what blue also (because it's never really been bench tested)

The other issue with LEDs is spotty growth since it's difficult to spread 3W crees, so you're right it's just not that simple.

I was partially joking about the CW/RB as my rocks look like turf scrubbers at the moment .

But yeah, that's why I said red and blue. Basically green algae have both chlorophylls a and b (if this book is to be believed). And if this is to be believed their light absorption peaks are in the areas of 430nm and 665nm for A and 460nm and 645nm for B.

From CREEs datasheets: XPE royal blue is at 465nm (I guess as close as it gets to the 430-460nm range) so all we need is a decent red - a little bit broader spectrum - (cree's reds are peaking at 630nm and is at only 10% intensity at 650nm so basically useless) and we're all set Anyone know of a red LED that is shin king in the 630-670nm range?

Anyway, I haven't really read the entire thread so maybe I'm repeating things that have been said before, if so I apologize.