Algae Scrubber Advanced

[Floyd R Turbo]

Way too few LEDs IMO. I run a typical 2-sided 4x6 waterfall with 6 reds and the equivalent of 1 blue on each side. When running the calc for the horizontal, the rule of thumb is a little less of a rule but rather a general shot in the dark. But the bare minimum is for comparable filtration, quadruple the size and at least 2x the light.

So for a vertical 4x6 (24 sq in) translated to horizontal, you would need 24x4 = 96 sq in and at least 2x the light, or 24x 660nm Reds plus whatever blue.

You're about 1/2 that size, so 40 sq in would still need, IMO, 10x 660nm LEDs. You have to make up for the inefficiency of the horizontal scrubber with more light punch = more LEDs.

I haven't seen a similar issue with vertical scrubbers, but generally when I tell people to increase flow I also tell them to increase light intensity and/or photoperiod duration in similar fashion.

Seems there could be many things going on here, so while all this above could be a reason, it might still come back to the boundary layer thing, or I could just be completely off the mark, since I don't have any experience with horizontal scrubbers.

 

[Chris Abbott]

So I will say what the above said expert will not! STOP thinking you can out think what has been figured and come back and ask questions about your theory!

 

[Chris Abbott]

so I'm going to check myself, make an attempt to test your theory's before you post if you dint want to get checked

 

[Floyd R Turbo]

so I'm going to check myself, make an attempt to test your theory's before you post if you dint want to get checked

So I will say what the above said expert will not! STOP thinking you can out think what has been figured and come back and ask questions about your theory!

Um, what? I can't tell if you're mad at me or what. I don't really know what you're trying to say here, JustinGR asked what I thought might be going on and I told him what I thought. It's hard to find anyone with a lot of non-dump-bucket horizontal experience, and no I do not believe that everything has been "figured out" even when it comes to waterfall scrubbers. I don't pretend to know everything either, if you read enough of my posts, when it comes to something I am pretty sure about, I give advice rather bluntly. When it comes to aspects that I am not sure about, I tend to give advice more from a theoretical perspective, or what "seems to make sense". Call them educated guesses.

All I was responding with was what I understand to be the general rule of thumb based on what others have put together. I stated that I don't have direct personal experience. But the general rule of thumb has been (since I've been talking about scrubbers, at least):

Waterfall scrubber, lit on both sides, for a given target filtration capacity, screen is size "A"

Waterfall scrubber, lit only on one side, for same capacity, screen is size 2x "A", with the same total amount of light, but now all on the same side (this was since revised to be actually double the total wattage of light for a single-sided scrubber, but that's another detail)

Non-vertical scrubber (slanted, horizontal, etc) for same target capacity, 4x "A" and then at least double the light.

Now, the horizontal "guideline" has not really been full tested, because vertical is so much more efficient, but if you go just by light density (wattage per actual unit of growth area surface) the horizontal scrubber that is 4x the dimensional area of the comparable vertical double-lit scrubber actually only have 2x the growth surface area, because you are only using one side. So to get the same "light density" you must double the total output to the screen. On top of that, horizontal scrubbers are not as efficient because of channeling, boundary layer issues, etc, so the more light, the better.

So now if I reverse the thought process, a 4x10 horizontal scrubber would be comparable to a vertical double-lit scrubber that is 1/4 the dimensional size, or 10 sq in. So a 2x5 scrubber. or 4 x 2.5. Whatever. Essentially, a 1/2 cube/day feeding capacity. So you would have 10 watts of CFL per side, total of 20 W for the current "high" light level, or 5W per side for low level. So the double-sided screen with 10W on each side gives each "exposure" of the screen 10W of light, or 1 W/sq in.

Now, converting out the lighting back to horizontal, you would want at least the same light intensity, which is 1W/sq in, or 40W, because your have only one side exposed, it is 4x10= 40 sq in. That is the MINIMUM light level for a horizontal scrubber. If you figure in that 660nm LED are more efficient, then 5x 3W Deep Reds would be the bare minimum light for a horizontal scrubber. Doubling that would get you to a much better light level, as well as a much better overall light coverage.

I go by an area calculation for LEDs rather than a wattage per unit area calculation, because it makes more sense since we are dealing with more focused point sources. maximum coverage of 1 660nm Deep Red for every 2x2 (4 sq in) growth surface area. So for 40 sq in, that's 10 LEDs. This is what I use for 2-sided waterfall scrubbers and it works extremely well.

4x6 scrubber - 6 LEDs per side
4x12 scrubber - 12 LEDs per side.

Time and time again, this works. So i am sticking to my advice that for a 4x10 horizontal, you need 2 rows of 5 LEDs, minimum. This does not include any blues, which I would run at either 1/2 power, or use 1W blues.

 

[JustinGr]

Floyd,

I think he's posting at me, and you are the "expert" he's defending. Not sure where he is coming from. This is not my first trip to the rodeo. I have sveral Inland dump style ATS that are doing great on other systems, and have for a long time. This design I am using is not new or a one off, but a system that has been employed for many, many years by others, and has historically good results. I am trying to figure out flow rates, and I believe this has a major impact on growth, in combination to lighting for this style of scrubber.

So back to the real topic. I will add another row of Red's on a second controller. I can tell you that my screen is almost completely covered in algae again since I cut the flow to 15%. I do think the water thickness over the screen contributed to the decline.

As for capacity, this sump is on a 40 gallon custom made tank that is compartmentalized into 4 10 gallon breeding cubes for clowns. Each cube as a pair of clowns, so the bio load is low. The sump holds maybe 12 gallons at most.

I'll get the lights ordered. Until then, I may increase the photo period to 24 hours for a little bit.

 

[Chris Abbott]

gentlemen apologies to both of you,Yesterday was not particularly kind to me and I let that overflow onto this thread and for that I sincerely apologize, many people including Turbo have been very helpful in they past. Thanks for the help!

 

[Floyd R Turbo]

LOL oh man have I been there!!!! No problem at all man

 

[reefermike1]

After much research I've decided to employ an ats on my 180 gallon tank. I've got a 30gallons in the sump and plan to add a 30-50 gallon prop tank in the future, so I'm basing this off a 250gallon total volume estimate. I'm starting to make a plan, and would like some guidance before I start building.

Id like to make my screen 10-12" wide and about 2 ft long. I'd like it to hang long-ways with one 24" t5 lamp hung vertically on either side. I'd also like to supply waterflow with a maxi-jet 1200 or similar powerhead. I'd like for this to become the back-bone filtration for my system if possible.

My main questions are- Will the screen be big enough. Will the mj1200 handle the flow, or if not what pump would. Will a single t5 bulb light 10-12" of screen? Or would there be a better lighting choice?

Thanks in advance.

 

[Floyd R Turbo]

Just out of curiosity, how did you arrive on that size of screen? Sizing is roughly based on feeding now instead of tank volume. See the post #'s in my sig below.

24 x 12 would be big enough for 24 cubes of food per day if it had enough flow and light.

Flow for that would need to be 24" x 35 GPH/in = 840 GPH at the screen, maxi-jet 1200 would be way too little and are horrible for head loss so you would be looking at a mag 12

Lighting for T5HO would need to be as many as you can cram in with reflectors, about 1 lamp for every 3" of vertical screen so about 3 or 4 per side, at least.

So, with that being said - I think you should re-size per feeding, it'll be a lot easier!!!

 

[SantaMonica]

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

 

[reefermike1]

Guess my research barely scratched the surface... Im really glad I posted before building anything. I've seen pics of some huge scrubbers so that's what I thought was needed.

So one watt of cfl 2700K per sq in.

35 gph per linear inch

and for every 12 sq inches lit on both sides your good for 1 cube of food per day.

no need to seed the algae it grows by itself

correct so far?

so if i made a screen roughly 7"x 7" put a 23watt cfl bulb on either side of it for 18 hours a day, and ran it with a mj1200, I should be able to feed around 3 cubes of food per day without having a nutrient problem in my tank. right?

 

[Floyd R Turbo]

7x7 = 49/12 = 4 cubes/day

23w per side would be the minimum light level, and yes 18 hrs/day.

7" x 35 GPH = 245 GPH minimum across the screen (after head loss, etc) and no a MJ1200 will definitely not cut it, trust me on this, they do not have a good head loss reaction.

You can count the slot pipe as the equivalent of 2' of head, so if the vertical head (difference between the water level that the pump is in and the slot pipe level) is 8", then you're looking at a head loss of around 3 feet. Plug that into any chart and look for 250 GPH and you're looking at a Rio 1100 minimum, probably a 1400 just to be safe.

An MJ1200 will maybe get you 190 GPH off the bat, but as soon as you have any algae that wants to grow in the slot/screen junction, it will drop dramatically, to under 150 GPH, and that lack of pressure will allow more algae to grow in the slot decreasing the flow more. Eventually you will end up with under 100 GPH. This is what happened to me when I ran a 6" wide screen on an Eheim Compact 1000 - I had an initial flow rate of 200 GPH and after a few months when growth kicked in, at the end of 10 days the flow was 60 GPH. You need a pump with some oomph.

 

[reefermike1]

Thanks a lot. Plan to start on it right away.

 

[screamingibis]

why not just split off your return to your sump for flow to ATS?

 

[Floyd R Turbo]

You certainly can, but the issue is that there is variable back-pressure over time at the slot/screen junction. There is also the possibility of something going down the overflow pipe and blocking flow to the screen, or to the other path, or both. So you have to have a full flow secondary path to prevent tank overflow.

One way to do this is using a Herbie or BeanAnimal type of system, or just having an additional standpipe that can take all the flow. But since this takes planning before building the system, usually you have to improvise.

One such way is to make a bypass pipe like this (forgive the crude hand sketch):

And for a basement sump, something like this:

The point is that you need to allow for enough of a water column to build up over the slot/screen junction, otherwise the water will take the other path. If you block the light at the junction, then this is a little less of a problem, but algae will still grow into the area and you will have a percentage of flow restriction.

 

[Brummie]

Modified the screen to increase diatom growth;

Going Brown;<br /><br />http://youtube.com/embed/QT2Qa6qQDtc?html5=1&fs=1[/url]

This following statement would suggest that horizontals should be removed from the sump for cleaning, which seems to be born out by my experience so far;<br /><br />

<br />The typical ATS community additionally contains a diverse mixture of protozoans and small invertebrates, especially nematode worms and insects in fresh water and small crustaceans and polychaetes in estuarine waters. Such an ATS floway is an autotrophically-based ecosystem. However, by examining the percentage of nutrients removed as TN (total nitrogen) versus DN (dissolved nitrogen), the floway nutrient sink can be demonstrated to be typically 30-40% derived from particulates in the water column (including plankton). Thus, the ATS ecosystem clearly has a heterotrophic component. As earlier microcosm research had shown (Adey and Loveland, 2007), particulates are captured not generally by the filtering of plankton, but rather mostly by capture of organic particulates. Some of the protozoans and invertebrates on the ATS floway could be capable of mucous web capture of particulates, but two of the most abundant organisms on ATS systems, diatoms and blue-green algae, secrete abundant mucous to encase their cells, attach themselves to the substrate and , in the case of the diatoms, provide mobility.<br />Most diatoms can function as both autotrophs and heterotrophs (based in dissolved organics), and some can switch from one source to another (Graham and Wilcox, 2000). Although it has yet to be investigated, it is likely that there is an internal transfer of nutrients and energy from organic particulates through the bacteria, protozoan and invertebrate sub- community to diatoms, and this may be partly the source of apparently higher levels of diatom photosynthesis on ATS systems.

 

[Floyd R Turbo]

Modified the screen to increase diatom growth;

Going Brown

<iframe width="560" height="315" src="//www.youtube.com/embed/QT2Qa6qQDtc" frameborder="0" allowfullscreen></iframe>

This following statement would suggest that horizontals should be removed from the sump for cleaning, which seems to be born out by my experience so far

Fixed the embedded video link for ya...

 

[Brummie]

Good bloke, as ever

 

[Chris Abbott]

Not even going to qualify it. ATS will help fix nutrient export issues! THIS IS A FACT! My screen still doe not grow the nice green turf but I suspect I haven't figured out the light to nutrient ratio. Who cares my sps grow and my LPS are out of control! Still think I need some info on micro nutes do if you can point it out thx.

 

[Floyd R Turbo]

^^ Is that posted in the wrong thread?