Algae Scrubber Basics

[Floyd R Turbo]

I'm not even sure what statement you are referring to, went back a few months on thei thread and still don't know, and can't remember details from 2 weeks ago...so...apology accepted I guess!!

 

[troublet55]

Scrubber build

Scrubber build

Well, I have wanted to build a scrubber for a while now and with the help of this thread and Floyd Turbo guiding me with LED's it is installed and functioning. Been running a couple weeks and has decent growth so hopefully my Nitrates and Phosphates will be lowered. I made the housing out of old glass tank lids and sealed it with Aquarium sealant. It sits on top of my 40 breeder sump perfectly.

Same basic design that many others have put together, 10x10 screen, running a dedicated pump that is putting out just shy of 350 gallons per hour. The lights are about 2 1/2 inches from the screen and currently I am running them 14 on and 10 off. I may have to trim down the screen to 8 inches if the growth is not acceptable or maybe purchase a stronger pump. Some pics of the scrubber:


View attachment 235185

I replaced the flex line for the drain with solid 3/4 PVC after I was satisfied the scrubber was functioning. I did not take pictures of the LED build (probably would not post them as I am not an electrician!) and I realize the heat sink should be vertical (still working the final mounting), there are 2 dedicated computer fans pulling air though the sump when the lights come on and the heat sinks hardly generate any heat. The parts for the LED's are:

2 Mean Well LPC-35-700 constant current drivers
6 3w Philips Rebel ES Royal Blue LED
10 3w-high power led warm white star emitter 160-180lm
20 3w-high power red led star emitter 660nm 670nm
2 aluminum heat sinks for 20x3w which are about 23 inches long

I will post up pics of the screen the next cleaning day, Please let me know what you think or if you see any areas I could improve on. Hopefully this helps out somebody looking for ideas.

 

[Mrlttran]

To the guys that are using this kind of light,how are you finding them so far ?

So after reading for hours, this seems to be a good light choice. Now I actually need to get off my butt and build/order. If I have a 150g mixed reef and feed about 2-3 cubes a day, how big should my screen be and what wattage should I order on the above light? I am going with a waterfall and the light will probably be 3-5" away from the screen.

 

[scolley]

Please let me know what you think or if you see any areas I could improve on.

Looks like a well executed DIY project. :thumbsup:

How big is that tank? That's a LOT of light you are throwing. I know a watt is not a substitute for true measures of LED light thrown, but it's a quick substitute (for loose ball park discussions). And you've to more than one watt per square inch of screen. I've not been keeping up... is that the standard now?

Also, how/why did you decide on that particular mix/ratio of LEDs?

Thanks.

 

[Reef Reactor]

I am planning a new big tank (96"x40"x30") and it will be on the window of my living room dividing the wall on the garden. I am thinking to have it under a dome where natural sunlight will be lighting it.

I am thinking to use a scruber for three diferente solutions to problems I may have:
1.-Filter the tank (obviusly )
2.-Cool the tank (thinking to introduce fans to put as much air on it to get water more cold and maintain temp on whole system)
3.-Save on lighting (thinking on have it over the dome and receive natural sunlight as whole tank.

Is this possible? Any suggestion about it? maybe I am not taking something in consideration.

Thanks ! Great Topic !!

 

[troublet55]

Looks like a well executed DIY project. :thumbsup:

Thanks!

How big is that tank? That's a LOT of light you are throwing. I know a watt is not a substitute for true measures of LED light thrown, but it's a quick substitute (for loose ball park discussions). And you've to more than one watt per square inch of screen. I've not been keeping up... is that the standard now?

The tank is 90 gallons with a 40 gallon sump, honestly I have read the thread a couple times and get more confused each time so I really do not know the true "standard" for watts per inch of screen.

Also, how/why did you decide on that particular mix/ratio of LEDs?

I read another post where someone had done the red and blue LEDs with those drivers and they worked well so I used that formula and threw in some whites just because. The whites may have to be removed or replaced with some more reds depending on the growth. I am still playing with how long to leave the lights on and if anybody has a suggestion I am all ears.

This tank is a new build and just a couple months old, I downsized from a 150 after it basically crashed while I was deployed for 7 months. I built the stand with a scrubber in mind and left myself plenty of room. So honestly I am not sure how much screen and light I need for best results. I feed around 2 cubes per day so I believe I have too much screen?

 

[scolley]

Thanks for the reply troublet55.

I have just a shade under one watt LED per square inch of screen myself. However, my LEDs are two years old. So your watts are working a lot (50%?) harder than my watts. Plus, I'm pretty sure I'm throwing too much light, because I consistently have burned spots in my algae matt. In fact, the matt extends several inches below the surface of the water. And while my LEDs are aimed at the matt above water, just the excess light that makes it to the algae under the water surface grows nice algae there. (Oh... I don't count that underwater mat as part of my watts/sq. in. calculation.)

So all that leads me to believe I've got too much light, and thus my question about yours.

Also, the whites won't hurt anything - regardless of what other people may tell you here. At worse they'll be less efficient at growing algae. But if white LEDs would not grow algae just fine, the whole reefing community using LEDs over their DTs would have figured that little bonus out years ago. Everyone with an algae problem would be switching to white LEDs. But that's not happening, is it?

My first ATS was almost all white, and it grew algae like gangbusters.

 

[scolley]

Ahhh... one more point troublet55.

If we accept that the right combo of red and blue is MUCH more efficient than using whites, that means my ATS LED should be even more less efficient than yours. Because mine's 1/3 deep red, the rest white. So with a higher ratio of red/blue to white in yours, that would be an even stronger argument for saying you are throwing a lot of light at that screen.

All of that presumes - of course - that I am actually throwing too much light at mine. For that's the basis of comparison that I'm using. And it's why I was curious how you came up with the numbers you are using.

 

[troublet55]

Scolley,

A couple questions if you don't mind,

How many hours per day are you leaving your lights on?

How many gallons per hour are you pumping?

And finally, do you go by cubes fed per day for size or a different formula?

The reason I ask is I built mine basically as big as I could since I have a pretty big bioload in my tank and I have always battled nitrates (even in my 150) so I thought bigger would be better? If I went solely on cubes per day I believe my screen is oversized. Thanks

 

[troublet55]

I have just a shade under one watt LED per square inch of screen myself. However, my LEDs are two years old. So your watts are working a lot (50%?) harder than my watts. Plus, I'm pretty sure I'm throwing too much light, because I consistently have burned spots in my algae matt. In fact, the matt extends several inches below the surface of the water. And while my LEDs are aimed at the matt above water, just the excess light that makes it to the algae under the water surface grows nice algae there. (Oh... I don't count that underwater mat as part of my watts/sq. in. calculation.)

Would the burned spots be able to be fixed by simply shortening the lighting period or adding a dimmable driver? I have the same feeling on mine but have not had it in operation long enough to make an informed decision. It seems to be going through the normal screen maturing process but time will tell.

I will be making the final lighting mounts utilizing mirrors to capture the light bleeding over so if I have too much light now, I will definately have too much then.

 

[scolley]

How many hours per day are you leaving your lights on?

20.

How many gallons per hour are you pumping?

I honestly have no idea. It's T'ed off my return and restricted with a gate valve for fine tuning flow. But if I look at my matt, there is a constant stream of water running down every inch of it. And there is not so much water that you don't see the contours of the mat though - it does NOT look like a flat sheet of water. No, you see every ripple in the mat. They are quite visible. So I guess that means it's not a LOT of water, but WAY more than enough to keep the entire mat both soaked and constantly refreshed with new water.

And finally, do you go by cubes fed per day for size or a different formula?

Personally I think "cubes" is a softer metric than the watts/sq. in. of matt I was referencing earlier. No such thing as a standard cube size or standard content. But without a more specific way to measure nutrients coming into the system, it'll have to do. I don't use it for sizing.

I used the sizing metrics stated in the front of this thread (not the very first, but the corrected ones) for my initial build, and found it to work. That's for water flow rate and screen size. But I made mine smaller because I feed lightly. If I were to translate the amount to the very, very loose "cubes" measure, I'd say I feed about 1/4 cube into a 33g DT daily.

For me my real metric is nitrates and phosphates. I rarely measure them because they are consistently so good. But a couple of days ago I went to the trouble because I'm working on a refund from Drs. F&S on a sick coral they sent, and they wanted confirmation of "pristine" water conditions. Salifert tells me my NO3 is less than 0.2 ppm (their lowest measure), but present. And my Hanna meter said PO4 is 0.04 ppm.

If those numbers were a lot more, I'd start worrying about improving my light, fine tuning my flow, or getting a bigger screen. But frankly things are pretty much exactly where I want them. So I let my little ATS's imperfections continue. They are doing a bang-up job. :thumbsup:

...I have a pretty big bioload in my tank and I have always battled nitrates (even in my 150) so I thought bigger would be better? If I went solely on cubes per day I believe my screen is oversized. Thanks

Well, as before, I did my sizing based on the early recommendations in this thread, then scaled it back to accommodate my low feeding. My bioload is high - don't scale by bioload. I've got a tank chock full of corals. You should size based on the amount of nutrients you put in. So I've got a reasonably high bioload (low fish load though) for a 33g. But I don't put many new nutrients in every day.

As for the "is bigger better" question, I can only offer an opinion that I cannot back up with experience. That is... if a systems has the right amount of light for the screen, and the right water flow over the screen, building that screen bigger than conventional wisdom says is necessary will only spread the algae growth over a larger surface. So it will strip nutrients out of the water faster than a "correctly sized" system. That may cause you to reduce your photoperiod to keep from completely stripping the system of nutrients. And that's not a bad thing at all. Short answer - if the light and flow are appropriate to the screen size, having a screen that's too big is not a big deal.

I hope that helps.

 

[scolley]

Would the burned spots be able to be fixed by simply shortening the lighting period or adding a dimmable driver?.

I would assume yes. But that also presumes that my problem is "hot spots", and not something else.

I will be making the final lighting mounts utilizing mirrors to capture the light bleeding over so if I have too much light now, I will definately have too much then.

I don't know about mirrors, but it's worth noting that I don't use any optics. And without mirror - or optics - a HUGE amount of that 1 watt per 1" sq. of screen is getting wasted. That probably helps explain why I have such nice underwater growth.

 

[_shorty_]

For me my real metric is nitrates and phosphates. I rarely measure them because they are consistently so good. But a couple of days ago I went to the trouble because I'm working on a refund from Drs. F&S on a sick coral they sent, and they wanted confirmation of "pristine" water conditions. Salifert tells me my NO3 is less than 0.2 ppm (their lowest measure), but present. And my Hanna meter said PO4 is 0.04 ppm.

exactly. Out of curiosity, are you running a skimmer?, or scrubber only? Any other chemical reactors like carbon or GFO?

Typically for hot-spots the most simple form of correction is to put more distance between the lights and screen. A relatively small amount of distance can make a difference.


On a side note - I mentioned before that I was piecing together a Ca Reactor and planned on plumbing it into my waterfall scrubber. I've been tuning in the reactor over the past week or more, and got her plumbed into the scrubber yesterday - so we'll see if the negative effects of each piece of equipment compliment and cancel each other. ( aka low pH from reactor, and DKH usage of waterfall scrubber )

I'll report back in a week or probably two.

 

[scolley]

exactly. Out of curiosity, are you running a skimmer?, or scrubber only? Any other chemical reactors like carbon or GFO?

I do run a skimmer; an SC-65 (since renamed as SCA-301 on eBay). A dirt cheap, hard working little nano skimmer. And I drop a bag of 1/2 cup high quality carbon (ROX) in my sump every two weeks. Plus I change something over 30% of my water each month. So it's not just the ATS. However, if we took the ATS out of the equation, I'd never have those solid nitrate/phosphate numbers.

As it is, my corals thank me every day by waiving their little polys at me all day long.

And thanks for the tip on the light distance.

 

[salty joe]

20.
As for the "is bigger better" question, I can only offer an opinion that I cannot back up with experience. That is... if a systems has the right amount of light for the screen, and the right water flow over the screen, building that screen bigger than conventional wisdom says is necessary will only spread the algae growth over a larger surface. So it will strip nutrients out of the water faster than a "correctly sized" system. That may cause you to reduce your photoperiod to keep from completely stripping the system of nutrients. And that's not a bad thing at all. Short answer - if the light and flow are appropriate to the screen size, having a screen that's too big is not a big deal.

I hope that helps.

That makes a lot of sense.

I would assume yes. But that also presumes that my problem is "hot spots", and not something else.


I don't know about mirrors, but it's worth noting that I don't use any optics. And without mirror - or optics - a HUGE amount of that 1 watt per 1" sq. of screen is getting wasted. That probably helps explain why I have such nice underwater growth.

It's my understanding that mirrors are not as effective reflectors as specular aluminum. Shiny aluminum. Each time the mirror reflects, the light has to pass through the glass two times.

exactly. Out of curiosity, are you running a skimmer?, or scrubber only? Any other chemical reactors like carbon or GFO?

Typically for hot-spots the most simple form of correction is to put more distance between the lights and screen. A relatively small amount of distance can make a difference.


On a side note - I mentioned before that I was piecing together a Ca Reactor and planned on plumbing it into my waterfall scrubber. I've been tuning in the reactor over the past week or more, and got her plumbed into the scrubber yesterday - so we'll see if the negative effects of each piece of equipment compliment and cancel each other. ( aka low pH from reactor, and DKH usage of waterfall scrubber )

I'll report back in a week or probably two.

Please do report on the Calcium reactor plumbed into the scrubber. I am planning the same thing. Thanks all.

 

[troublet55]

As for the "is bigger better" question, I can only offer an opinion that I cannot back up with experience. That is... if a systems has the right amount of light for the screen, and the right water flow over the screen, building that screen bigger than conventional wisdom says is necessary will only spread the algae growth over a larger surface. So it will strip nutrients out of the water faster than a "correctly sized" system. That may cause you to reduce your photoperiod to keep from completely stripping the system of nutrients. And that's not a bad thing at all. Short answer - if the light and flow are appropriate to the screen size, having a screen that's too big is not a big deal.

Scolley, That is exactly what I was thinking.

It's my understanding that mirrors are not as effective reflectors as specular aluminum. Shiny aluminum. Each time the mirror reflects, the light has to pass through the glass two times.

Salty Joe, I have not heard this and I will definitely look into it, Thanks!

For me my real metric is nitrates and phosphates. I rarely measure them because they are consistently so good. But a couple of days ago I went to the trouble because I'm working on a refund from Drs. F&S on a sick coral they sent, and they wanted confirmation of "pristine" water conditions. Salifert tells me my NO3 is less than 0.2 ppm (their lowest measure), but present. And my Hanna meter said PO4 is 0.04 ppm.

Scolley, This is what I am hoping to achieve, On my other tank I constantly battled Nitrates to the point I had all but given up. I hope that the scrubber along with better maintenance by me gives me positive results.

 

[_shorty_]

It's my understanding that mirrors are not as effective reflectors as specular aluminum. Shiny aluminum. Each time the mirror reflects, the light has to pass through the glass two times.

I'm not saying this is false, but 'logically' (in my mind at least) this doesn't seem right. If you could clearly see your image in polished aluminum ( and if your aluminum reflector is indeed polished, which most aren't ), I'd completely agree.
Otherwise, im not sure i buy it. Technically yes, it would have to pass through the glass twice, but I'd still think that this is negligible compared to the amount of reflection comparing the two ( at least in most cases )

 

[Floyd R Turbo]

A specular reflector (highly polished aluminum) is a mirror finish, without the glass, and it is what almost all reflectors for commercial/industrial lighting is made from, because of it's extremely high relfectivity percentage. If you had a mirror made from polished aluminum, it would be 1) pretty much like any other mirror in your home and 2) really expensive. But that argument aside, you can't put either of them underwater, and with 120 degree non-lensed LEDs, you really don't lose that much light to the side, the majority of useable light is directed forward in a cone that is 60 degrees off top dead center of the LED, so I would not worry about reflectors or lenses on your LEDs. It is cheaper and easier to just add a few more LEDs.

As for the discussion about LEDs burning, from my experience if you run royal blues at full power (current) and put them 2" from the screen, then will cause photosaturation - a bare spot on the screen. I have one screen that is 4x6 with 6 reds on each side on 2" centers with a single blue in the middle of that rectangle, and on one side of the screen, it is always bare when I scrape it. The other side is not, strangely enough, maybe because that LED is not as good of a bin or something...not sure. But, the bare spot is not prevalent until I scrape, i.e. the algae mat grows around it and over it, from the sides. I really need to re-wire that particular fixture with half-current LEDs.

As for the discussion about watts/sq in, what I have come up with, based on my experiences and that of others, is a "minimum" and "maximum" for coverage based on quantity of LEDs per unit area as follows:

For "minimum" coverage: one 660nm 3W LED on each side of every 8 sq in of screen
For "maximum" coverage: one 660nm 3W LED on each side of every 4 sq in of screen

Then, add in the other supplemental colors such as blue and whites, but I run all of these "secondary" colors at 50% current by wiring in a current divider sequence as I recently posted. The rationale being that these LEDs have a higher radiant flux and/or lumen output, and because they are LEDs and are so much more focused sources of light, this can tend to cause photo saturation, which will tend to disallow algal growth on the long term (hence the bare spot on my year-old LED scrubber).

And also a word about sizing, I'm with scolley on the fact that it is very difficult at best to quantify all food sources into cube-equivalents accurately. So making it bigger than the current guidelines recommend is not the worst thing you could do, I have been recommending no larger than 2x the feeding guideline for a while now.

Also in conjunction with that, the larger the tank, IMO, the tank volume comes back into play as a secondary factor of sorts. The thought process here is that with a small feeding-based scrubber and high water volume, you have less "turnover" of the water volume in terms of percent of total volume per unit time. So once you get to about 150-200 gallons, start increasing the width of the scrubber to get higher turnover, or at least size the scrubber wider rather than taller.

But however you look at it, there is a fair amount of wiggle room as far as screen sizing goes, and I also agree that using only feeding as a sizing factor is logically restrictive. As with many thing in this hobby, there are many factors that go into each thought process. Feeding and tank volume are large factors, but so is the overall "bioload" of the system, as well as diversity of life, and presence other filtration components and husbandry techniques.

Then there is the other factor that most don't really consider, and that is the diversity of life that the scrubber adds into the system. Most report an increase in growth of sponges and other organisms when a scrubber is included in the system. A scrubber (or a good refugium for that matter) provides a breeding ground for all kinds of life, which can quite often fill in a gap in the food web that is often missing. But I digress.

 

[salty joe]

But I digress.

No, all things algea scrubber! Your posts are great.

 

[troublet55]

so I would not worry about reflectors or lenses on your LEDs. It is cheaper and easier to just add a few more LEDs.

On my setup I am more concerned with stopping all the excess "bleedover" light coming from my scrubber. I am only half joking when I say that the excess light coming from the vents and doors on my stand looks like the refugium is an all night disco. I need to build a permanent mount that is easily removable for the LEDs anyway so I was thinking I may as well utilize what I have.

Then, add in the other supplemental colors such as blue and whites, but I run all of these "secondary" colors at 50% current by wiring in a current divider sequence as I recently posted.

I had a problem while wiring up one of the LEDs using this method. The first fixture worked as advertised no issues, On the second fixture, half of the lights would not work unless they were wired in series? I re did every connection at least three times and re verified numerous times with the same results? So that fixture is running full out, I guess I will get a good comparison on which way works best for my setup. I am sure I missed something simple, but it was strange.

Also in conjunction with that, the larger the tank, IMO, the tank volume comes back into play as a secondary factor of sorts. The thought process here is that with a small feeding-based scrubber and high water volume, you have less "turnover" of the water volume in terms of percent of total volume per unit time. So once you get to about 150-200 gallons, start increasing the width of the scrubber to get higher turnover, or at least size the scrubber wider rather than taller.

The sizing will be a long process for me as this is a new tank (2 months old) that was started with completely dead rock and sand, large bioload and probably feeding too much. It will be a long time before everything is "solidified" as far as sizing.

Then there is the other factor that most don't really consider, and that is the diversity of life that the scrubber adds into the system.

I have thought of this as a major plus for the scrubber system, the more diverse (and reefsafe) lifeforms in my system the better.

And one last note, whoever came up with the saranwrap idea for splash and drip reduction can stop by anytime for a beer! lol was getting ready to replace the pipe due to an annoying splashing sound due to a "streamer" when I took another look into the thread and found that advice, dead silent now!