vahegan's UAS test

[vahegan]

I have finally made my experimental UAS today. Sorry for the poor quality of photos - made with the iPhone, was too lazy to pick up a descent camera with proper processing.

For light source I used the Surexi F1 LEd modules with optimal for photosynthesis spectra, purchased at the TheLedStore (http://www.theledstore.com.au/product_p/ls0017.htm). Initially I planned using these for a first generation ATS, but never managed to actually finish building one. Since this new design was much simpler to make, I decided to give this a go - although I believe that the old design might be more efficient (since at least, there is no light loss on the thick glass and the algae that will grow on it). Anyway, if I don't like this design, I can always take out the screen convert it to the old style scrubber.

Here are the Surexi modules, the match box is for size:
http://algaescrubber.net/forums/attachment.php?attachmentid=2294&d=1336573976
The F1 spectrum module contains 12 red LEDs (with 660nm peak) and 4 royals blues (450nm). Each module is good for up to 5W power, made in wet-proof case (IP66) and has an integrated 60 degrees lens.

I cut 4 50cm long and 6cm wide aluminum sections to serve as the construction base and a heatsink for the LEDs.
http://algaescrubber.net/forums/attachment.php?attachmentid=2295&d=1336573976

I attached the sections to each other with rivets, then drilled holes and tapped threads to attach the LEDs (using a thermal compound, of course).
http://algaescrubber.net/forums/attachment.php?attachmentid=2296&d=1336573976

I attached a low-cost chinese driver on the back. It is capable of up to 90V output at 300mA. All the LED modules were connected in series, with 10V voltage drop on each. This present setup yields 24W of power, if I replace the driver I can safely get up to 40W power from the same LEDs, but I believe there is sufficient light already, to start with.
http://algaescrubber.net/forums/attachment.php?attachmentid=2297&d=1336573976

I processed the canvas like a cactus using the saw, as SantaMonicsa suggests in FAQ. I attached an airstone on the bottom using plastic ties, and then I hung the screen on a plastic rod.
http://algaescrubber.net/forums/attachment.php?attachmentid=2298&d=1336573976

[vahegan]

I hung the screen near the side wall in the sump, resting the plastic rod on front and rear walls of the sump, connected the air pump and turned on the LEDs. The photo isn't good since the light is too strong.
http://algaescrubber.net/forums/attachment.php?attachmentid=2299&d=1336575178

My tank is presently algae-ridden and I hope that all these algae will gradually move to the screen.
The tank is 250l (about 65g) mainly soft reef with Deltec MCE-600 skimmer, a Blue tang, a Premnas clownfish, and 2 mandarin dragonets. Daily feeding of one frozen cube and about as much live tubifex worms (mainly for the dragonets)

http://algaescrubber.net/forums/attachment.php?attachmentid=2300&d=1336575178

http://algaescrubber.net/forums/attachment.php?attachmentid=2301&d=1336575178

I will report in a few days if there is any progress.

[kotlec]

Few weeks is more realistic schedule.

[SantaMonica]

Good first try.

One thing, with any scrubber, you want to try to not have any area of the screen that does not get bright direct light. Area that get weak light will grow dark, die, and reduce filtering; thus the the larger areas will actually make the scrubber weaker. If possible, re-do the screen so that all of the screen is within about 3 inches of an LED.

Also, for one cube a day, a 1-sided screen side of 24 square inches (4 X 6) is probably best.

[vahegan]

Few weeks is more realistic schedule.

Yeah, I mean, I hope to get any growth at all on the screen within a few days.


Good first try.
Thank you, SantaMonica!


One thing, with any scrubber, you want to try to not have any area of the screen that does not get bright direct light. Area that get weak light will grow dark, die, and reduce filtering; thus the the larger areas will actually make the scrubber weaker. If possible, re-do the screen so that all of the screen is within about 3 inches of an LED.
Yeah, its about 2" between the LEDs horizontally, and about 2.5" vertically. The screeen extends some 4" up the first row and as much down the lowest row. So it basically fits within your recommendation, except for an extra inch on the top and on the bottom


Also, for one cube a day, a 1-sided screen side of 24 square inches (4 X 6) is probably best.
Well, the effective size of my screen now is about 10"x11" which is about 4.5 times more than you suggest.

Please note, however, that besides one frozen cube daily I also feed about as much of live tubifex worms soaked in Selcon, for the dragonets. Selcon adds a lot of phosphate. At least, in my previous system (which was half of the volume of present one) the phosphate went very high (about 2ppm) within a few months after I started feeding the dragonets - so that I had to dose Lanthanum chloride to get rid of it. I don't want to repeat this in the new system and I hope that the scrubber will help me to keep the phosphate under control. I want to be on the safe side and I'd rather have some extra scrubber power at hand before its too late. Besides, I am not sure yet that this type of UAS will be as efficient as conventional ATS.

[vahegan]

Watching the screen carefully this morning, I have noticed a light brown tint on the "cactus needles".
Absolutely not visible under the bright light, but distinguishable when the lights are off. So I hope, it is gradually starting up...

[SantaMonica]

Not bad for one day.

[vahegan]

Daily update: Inspected the screen again this morning. Virtually the same as yesterday. Maybe the tint is getting more even throughout the screen and slightly darker, yet it is still barely distinguishable and again, only when the lights are Off.

[vahegan]

Update: The screen is getting darker brown - clearly visible when lights are Off and barely visible under lights On. It is yet far from being anything scrapable, however.

The pic shows it to some extent, though not very clearly:

http://algaescrubber.net/forums/attachment.php?attachmentid=2330&d=1336992522

Also, after two more days, I noticed a strange thing today: it seems to me that there is more algae growth on the edges of the screen, where there is less light falling and less bubbles rubbing it. I can think of nothing that would explain this...

------------

I have an idea: Instead of the air wand, why not use a smallish (something like 250-300l/h will do just fine) internal pump, with an air line entering near the impeller? Will probably also need something like a bubble plate to distribute the bubbles evenly, like they do in skimmers, but maybe in a compact area around the screen this won't be even needed. The benefits are: no need for a possibly noisy air pump, a better flow of bubbles (accompanied with a better flow of water), and an all-integrated solution. I am planning to add a mirror to my setup - the screen will become enclosed between the mirror and the wall then - I can give the pump a try at the same time. What do you think?

[Floyd R Turbo]

Per your post on my thread, you might try the diffuser grating. You can just put one matchbox-sized piece on the glass in front of each one, or one piece covering the whole area (which is probably easier). You can find that material in a hardware store that carries ceiling tiles (like the ones that go in a 2x4 recessed grid ceiling). It's called a "prismatic diffuser" and is actually what they use in some light fixtures ("troffers" is what we call them here)

[MorganAtlanta]

If you use the diffuser grating, you can paint the top and bottom so that the only areas of the screen that get light are the brightly lit areas in the middle, which would resolve SM's concern. Also, it would stop algae growing on the airstone.

You might also consider putting something behind the screen to block light from going into the sump, as you'll likely get a lot of algae growing in there eventually.

What are your N and P measurements currently?

[SantaMonica]

Also, more/larger bubbles will diffuse more.

[vahegan]

Thank you very much for your input, guys!

Bud, I am afraid these diffusers aren't available in my country. I can only try to order those from the Internet, but it'll take 3-4 weeks until they are delivered...

But these Surexi modules I use they aren't like your common LEDs, they were designed for agricultural lighting and there is already a sort of diffuser on the top of these LEDs. I'll try to make a better photo tomorrow.

I think I will also clean the screen tomorrow.

MorganAtlanta, I do plan installing a mirror behind the screen, maybe somewhere next week. I will have to silicone a piece of glass behind the mirror to prevent the amalgam from contacting the water, and will have to wait a couple of days until silicon cures before I put it in my sump. There is already some growth on my skimmer wall, which is just behind the screen. I wonder whether there is growth on the inside wall of the skimmer as there are lots of bubbles rubbing it all the time. My fiend is now trying to grow algae in the skimmer, he inserted a screen into the MCE-300 hang-on skimmer and is lighting it from the outside. A very interesting approach, in my opinion.

Unfortunately no one has commented on my idea of replacing the air wand with a skimmer style pump. I experimented a little today: I cut a slot in a thick walled PP pipe and drilled a hole on the opposite side to insert the pump pipe.

http://algaescrubber.net/forums/attachment.php?attachmentid=2370&stc=1&d=1337455603

http://algaescrubber.net/forums/attachment.php?attachmentid=2371&stc=1&d=1337455603

I also inserted a piece of screen horizontally in the pipe to serve as a "bubble plate". I experimented with two small pumps: a had a 200l/h and a 450l/h pump lying around but wasn't getting sufficient bubbles. The next size pump I have is way too strong, about 2000l/h, will try to get something like 800-1000l/h tomorrow.

There are very fine bubbles coming out of the slot, anyway. SantaMonica, do you think its better to have larger bubbles?

As for N and P: they are not detectable with the tests I presently have (API).

[SantaMonica]

As long as there is enough airflow, the slot should work.

[vahegan]

OK, today it was day 11, and I did the first cleaning.

before clean
http://algaescrubber.net/forums/attachment.php?attachmentid=2374&stc=1&d=1337523363

after clean
http://algaescrubber.net/forums/attachment.php?attachmentid=2375&stc=1&d=1337523363

Underneath brownish and slimy algae in some spots there was also green algae which was very hard to scrape off the screen (using an old credit card). In some places it was dark green, in some other - light green, and in a couple of spots it was light-yellow-green. I remember SM has mentioned somewhere that yellow color is an indication of algae dyeing off so I assume I was a little bit late with my first cleaning.

Anyway, I was surprised to see any green algae at all on a completely new screen at its very first cleaning. Although the amount of algae grown was too little to talk about any nutrients export, I hope that these are signs that my scrubber is on the right path.

One thing I'd like to mention: looking on the screen after cleaning, it seems that there is less algae directly in front of the LEDs, and more on some distance from them. i.e. my LEDs are placed in 2 rows, and there are 3 rows dark from algae on the screen and 2 whiter rows - just in front of the LEDs. I assume that light is too strong there and burns the algae. Perhaps I really need to find a place that sells those diffusers online somewhere.

[Floyd R Turbo]

At this point, don't clean any of the green algae off. Just rinse away the slimy stuff and maybe a gentle rub with fingers. I scraped my screen down completely (didn't scrub, it just pretty much came off) on Monday and my growth is very low.

[vahegan]

Yeah, thanks, Bud! Next week will be less vigorous in my attempts to clean the screen...

[vahegan]

My friend has just sent me the pics of the screen that he placed inside the Deltec MCE-300 skimmer a week ago. the screen was lit by a 23W compact-fluorescent bulb.

I believe the result is very promising for a new screen, just one week old. This can be the simplest scrubber solution for the owners of hang-on skimmers with clear walls.

http://algaescrubber.net/forums/attachment.php?attachmentid=2402&stc=1&d=1337977455

http://algaescrubber.net/forums/attachment.php?attachmentid=2403&stc=1&d=1337977455

[Garf]

Sorry for being blunt, but how are those photo's promising.

[kerry]

Compared to my 10G CFL test unit they are awesome!!!! Mine is like 5 weeks older and is not as far as this it.

[Garf]

Kerry -are you talking about the skimmer pics. I was

[kerry]

I was talking about the screen growth pics. My 10G unit is a slow starter or something????

[vahegan]

Kerry -are you talking about the skimmer pics. I was

I do think that it looks pretty well for a fresh screen that has never been used before.
Any better examples of using a fresh screen in an UAS setup?

Here is, for example, Floyd's screen on day 7:

http://algaescrubber.net/forums/attachment.php?attachmentid=2029&d=1334403813 (http://algaescrubber.net/forums/showthread.php?1836-Floyd-s-LED-UAS-test&p=18948&viewfull=1#post18948)

We all know how well his setup has been growing lately. That's why I think that skimmer screen pic is promising.

[kerry]

Its great for the first week, keep us posted on the next cleaning.

[vahegan]

OK, back to my system. I cleaned the screen for the second time today (day 17 since the scrubber inception, day 7 since last cleaning).

Here are the pics:

Before clean:

http://reefcentral.ru/forum/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=1230

After clean:

http://reefcentral.ru/forum/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=1231

I believe my scrubber is gradually improving. There was more growth this time, compared with the first cleaning, and it is more the 3D type.

After cleaning I attached two laser printer transparencies to the airstone, to confine the bubbles closer to the screen, as Floyd suggested. I also noticed that there was more growth where the screen somehow curved to an angle and bubbles rubbed it better at that spot. So placing the screen at an angle may also promote better algae growth.

One more thing: the algae on the lighted side were lighter color, almost colorless. Whereas on the other side they were dark color (the picture shows the dark side). But the volume of algae growth was approximately the same on both sides.

The algae wasn't as easy to clean as Floyd suggested. Certainly, couldn't clean it by the fingers over the sink, had to work it out actively with an old toothbrush.

Also, it stinked terribly at my first clean. This time there was no foul smell.

[kerry]

Thats a great improvement, I hope to clean mine this evening or Monday morning, I will get pics to. I have been lazy with the fish stuff this holiday weekend. I have so much work to do now, I didn't water change any of my FW tanks this weekend yet.

[vahegan]

OK, I cleaned the screen for the third time today.

Screen before clean:

http://reefcentral.ru/forum/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=1483


Screen after clean:

http://reefcentral.ru/forum/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=1484

There is clearly more growth than last time, however this time thre was only growth on the lighted side and virtually nothing on the other side of the screen. I think, the time has come to attach a mirror behind the screen.

Algae are gradually disappearing from my display tank, there is significantly less algae on LR now.

I am planning to add 1ppm of nitrate tomorrow. This corresponds to 2.5ml of stock solution (19.5g of calcium nitrate dissolved in 50ml of water) per my 250l system. I suspect that the system lacks nitrate and the algae do not grow well on phosphate alono so I hope that adding some nitrate will promote algae growth on the screen. Besides, some nitrate in the water can be beneficial also for the corals.

[Garf]

Adding nitrate is very questionable. As you stated earlier, algae has a hard time on phosphate alone. You are trying to make your display better, not your scrubber. If your display is getting better I would carry on as you are. If you have a load of phosphate put a bit of GFO in to reduce it.

[vahegan]

Nope, not having lots of phosphate yet, just out of the fear of it ;) My previous system suffered from lots of phosphate (had to feed lots of live tubifex worms to keep my dragonets happy). So now I am trying my very best to prevent from that happening again. I have a bit of GFO, and a scrubber, and a better skimmer, and I do dose a bit of VSV daily in the hopes that my phosphate won't build up again. As for nitrate - a friend of mite was dosing nitrate even without a scrubber. Adding 1ppm was eaten completely by the night, 5ppm was gone in a couple of days... Corals seem to eating it too

[vahegan]

OK, so my scrubber is just over 1 month old, and I cleaned the screen for the 4th time this Sunday.

before clean:

http://reefcentral.ru/forum/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=1567
after clean:

http://reefcentral.ru/forum/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=1568

The growth is getting more 3D type but, to say frankly, I am a little bit disappointed with this scrubber type. After a month of running, I expected to harvest significantly more algae from the screen. I am gradually thinking of converting my UAS into a conventional waterfall-type scrubber in the hope to get more growth on the screen.

I must admit that almost all the algae in the display has disappeared during this one month (will post an updated general tank photo soon). I don't know where all this algae went since I did not harvest that much during my 4 cleanings so far.

I also cleaned my skimmer this Sunday. Some of the light that passes through the screen falls on my Deltec MCE-600. Unfortunately, don't have any pics of ir, but I was amazed by the amount of algae grown on the internal clear wall of the skimmer. Perhaps several times more than on the screen. Clearly, high turbulence incide the skimmer is responsible for this growth since the light falling there is much smaller than on the screen (I am getting virtually no growth on the opposite to LEDs side of the screen and the skimmer must be getting even less than that side).

This brings me back to the idea of using a skimmer pump for supplying bubbles to the screen. Unfortunately the pumps I have were not able to suck sufficient air at the depth of about 40-45cm (16-18"). I do not want to use too powerful a pump (over 500gph) - if I use that powerful pump, I'd rather convert to waterfall type scrubber which I still think is more efficient. I'll probably give this idea one last try with an 300gph pump I have lying around. Just need to find some time to try this out...

One more thing to try is to dose some ferrous gluconate to promote algae growth...

In the meanwhile, my friend had sent me a photo of the screen placed in the MCE-300 skimmer and lighted by a compact fluorescent bulb. This pic was made in just 3 days after cleaning:

http://reefcentral.ru/forum/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=1569

I think the growth is very impressive for 3 days! (well, I must admit that his nitrate is over 50ppm and hence there is plenty of food for the algae).

[SantaMonica]

I think it's your flow. Half of your screen looks to be getting no bubbles at all.

[vahegan]

Thank you for the comment, Santa.
Well, visually there are lots of bubbles at the "bald-looking" vertical section of the screen. However looking at this week's first uncleaned photo, this is exactly the part not covered by the transparency film. Judging from that I assume that although there is lots of bubbles there, they are not "rubbing" the screen properly /too little turbulence/.

Perhaps adding the mirror/glass just behind the screen will solve this issue. It will serve the same function as the tray in latest mod of the scrubber (plus the added bonus of redirecting the light back to the screen rather than to the skimmer). Donno why I didn't proceed with this idea yet. Will try to proceed further in that direction...

[vahegan]

I missed my last week's report, but there was nothing spectacular. Neither it is this time. It took me now about 10 days since my last cleaning. This time the algae are sort of reddish-brown color. The amount of algae grown is about the same as before.

Before clean, front side of the screen:

http://reefcentral.ru/forum/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=1986

Before clean, back side of the screen:

http://reefcentral.ru/forum/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=1987

Scrubbed algae: the larger pile is from the front side and the smaller is from the back
I used a piece of rigid plastic for scrubbing. The toothbrush is for size only.

http://reefcentral.ru/forum/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=1988

The screen after cleaning

http://reefcentral.ru/forum/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=1989

Well, I am sort of disappointed since I don't see any progress. I am soomewhat worried about the efficiency of this scrubber since I am now trying to wean a wild caught regal angel who refuses to eat the food I am offering and is very shy. I am overfeeding in the hope that he would pick some food from the rocks (he is constantly trying to nip something from the rocks but hides as soon as I feed and doesn't show up until all is eaten up by other fishes). Well, this is some extra load on the system and I worry that if the scrubber cannot handle it, my nitrate/phosphate may grow. Will see...

I finally got a piece of mirror yesterday and glued it to a piece of glass on its back to prevent the potential contact of aluminum coating with marine water. Will put it just behind the screen when the silicon cures - this will return some light to the back of the screen abd in the same time will sort of constrain the path of air bubbles so that they better rub the screen. Will see if this is of any help at all.

In the mean time I am thinking of trying to start the old waterfall-style scrubber in parallel to UAS. Actually, I almost have everything for it, just need to purchase some 660nm LEDs and a driver. I believe this will be an interesting test of UAS vs. waterfall scrubber - since they will operate in exactly the same conditions, it will show us which type is most efficient

[Garf]

With regard to the tang, is he not eating nori either !!

[SantaMonica]

Looks like it's is better without the clear sheets.

Yes putting something behind it is always better, to keep the bubbles on the screen. And getting light to the back side is always better too.

[vahegan]

With regard to the tang, is he not eating nori either !!
Hi Garf! Thank you so much for your advice! I have a regal tang which eats just everything! No problem at all.
The problem is with the newly acquired regal _angel_ (Pygoplites diacanthus) who refuses to pick any unnatural food.
Actually, I never offered him nori - maybe this is a good idea - he could try it since he is nipping on algae on the glass.

[kerry]

Mine will eat the algae from the screen.

[vahegan]

Looks like it's is better without the clear sheets.
Yes putting something behind it is always better, to keep the bubbles on the screen. And getting light to the back side is always better too.
Yeah, thank you, Santa. Will give this idea a try. Will remove the clear sheets and instead will try to jam the screen between the side glass and the mirror: maybe half an inch between them, or so.

[vahegan]

Mine will eat the algae from the screen.

Kerry, you are talking about an angel, don't you?

Mine is constantly picking something on the live rock, I can't see whether he is getting any real matter there. Whenever I feed, he hides immediately and doesn't show up until everything is eaten up by other fishes. Seems that he doesn't recognize prepared food as edible stuff...

[kerry]

My angel and tang will eat algae from the screen.

[vahegan]

My screen is in the sump, they have no access to it. My sump is on the same level as the display, its actually a section in the left of the tank. But they both nip on the algae growing on the glass wall which is between the sump and the tank. I'll try to attach a sheet of nori there to see whether the angel would try some.

Thank you all, guys, for your input on this matter. I posted questions on weaning the angel on many forums, but nowhere got as much useful advice as here in an unrelated forum...

[Garf]

My tangs eat more nori if it's cut up into 3 to 5 mm squares and allowed to float around the tank. Just a thought !

[vahegan]

Thank you, Garf!
Will try it both ways.

My concern is, the angel never touches anything floating in water (I even tried live baby endlers - strange that none of my fishes recognized them as food - perhaps they lived too long in a vegetarian home). The angel hides whenever there is floating stuff in the water and comes out for grazing when its clear again. That's why I thought of rather attaching it somewhere on a clip so maybe he would have it that way - in the hope that it may sort of look more "natural" to him.

[vahegan]

It was the regular screen cleaning day today.

Screen front before clean (note the amount of algae on the clear plastic sheet)

http://reefcentral.ru/forum/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=2091

Back side of the screen. Almost no growth.

http://reefcentral.ru/forum/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=2092

Scrubbed algae. The largest pile (left) is the algae collected from the clear plastic sheet, the second pile is from the screen front, and third - from the back. There was almost no algae grown on the clear sheet on the back side of the screen.

http://reefcentral.ru/forum/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=2093

---------------------

I desided to remove the clear plastic sheets and install a mirror, as planned.

I siliconed a glass to the back of the mirror for protection, and attached small pieces of acrilic on the top, using cyanoacrilate (superglue) to mount it on the front and back glass of the sump.

http://reefcentral.ru/forum/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=2094

The new construction in action. Let's see the crop in a week...

http://reefcentral.ru/forum/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=2095

[SantaMonica]

Light on the back side will make a lot of difference.

[rygh]

The thread is a bit old, but I was wondering how you liked those LED modules??
I have been thinking of using them for my new scrubber.

[vahegan]

Well, it has been over a year since I last posted here. During most of this time, I was getting very mediocre results with the UAS scrubber. I have been weighing the scraped and squeezed algae every week, then drying it up and weighing again for more consistent weight results. A week's average harvest was about 10-15 gram in squeezed wet algae, or about 2-3 gram of dried matter. It was not the 3D matter though, but something like it was shown in the photos in my previous posts.

So, I was not posting, because I did not see progress and was quite disappointed with the UAS scrubber. I was actually planning to convert it to the waterfall type, but never had the time to do this. But suddenly, this scrubber started producing 3D growth in the past couple of months. I don't know why the maturing took so long, but now the harvest is 3D stuff. The weight of squeezed wet harvest for two week's growth is about 67 gram now. I am attaching the photos.

[vahegan]

P.S. Forgot to tell that the growth is only on one side of the screen, the other side is bald. There is also some dence growth on the glass, which I have to scrape with the razor each time when I clean the screen. It comes out as sheets of dense algae matter, a few grams of wet weight.


The thread is a bit old, but I was wondering how you liked those LED modules??
I have been thinking of using them for my new scrubber.

Yes, I am happy about the LED modules, they perform quite well and did not degrade over time.

[Floyd R Turbo]

Did you change your feeding habits?

The UAS was originally touted to be the answer the break-in time that a waterfall screen takes. Your example is just one that clearly indicates this is not the case. My screen did the same as yours, but it really took off when I removed almost all the fish and reduced feeding significantly.

[vahegan]

Did you change your feeding habits?

The UAS was originally touted to be the answer the break-in time that a waterfall screen takes. Your example is just one that clearly indicates this is not the case. My screen did the same as yours, but it really took off when I removed almost all the fish and reduced feeding significantly.

Hi Floyd,
No, feeding habits are pretty much the same, and the fish count also. The system is stocked quite heavily for the volume (about 65 US gallon), but I mainly feed live blackworms (which I enrich with Selcon), and my screen is well oversized (almost a full letter-sized screen) for this system - plus I have a Deltec MC600 skimmer running there too. I don't know why the break-in time was so long...

[Floyd R Turbo]

I feel this is because

1) LED intensity will overpower growth initially for a certain period of time. Until you get a deep base formed, your growth will not bounce back from cleaning.

2) plastic canvas, while idea for waterfall screens, is not ideal for submerged UAS use. I'm going to go out on a limb here and say that it just takes time for the algae to root into the actual material on a UAS, then when it does, it can absorb the incoming light better and grow faster after cleaning. My screen has become progressively more 'stained' green, and this appears to not be so much staining as it is impregnation of the screen with algae spores. So after about a year roughly, it seems that the screen might hit a turnover point where growth can easily bounce back under high intensity LED light.

The difference with the waterfall screen is that the algae can form a mat in the holes and for some reason will hold on better in there, and the growth bounces back from that base and not so much the actual screen material itself. I have to scrape my waterfall screen hard. I barely have to scrape my UAS screen, even after 1.5 years of running it - most of it comes off just by grabbing it.

[vahegan]

What I find interesting - in the past months, it WAS growing algae (and yes, the holes between the net were even filled up better than now) but it was just different type of algae. Indeed, it required much effort to scrape off the screen. And yes, the screen was stained with unremovable algae from the start - actually, it was growing algae on both sides at that time.

Whereas the new type of algae is easily removed by one simple movement of the hand - if I scrape and wash after that, I do this only to remove any parts and bits remaining, so that they don't go back into the tank. Requires a very light, superficial effort - no hard scraping needed. The stain algae is still there on the screen, of course, but it doesn't produce much matter.

I suspect, maybe it took the "2D algae" a year to pull out some type of nutrients that were accumulated in the tank, and now the nutrient supply is changed to the type which is best utilized by the 3D variety?

[SantaMonica]

Yes, high nutrients grow dark, which block light. Low nutrients grow light, allowing 3D.

[Floyd R Turbo]

Vahegan, so define the type of growth you had in each of the 2 instances

In the past, firmly attached algae was:

Now, the less strongly attached algae is: