Anyone use LED's for Lighting a Scrubber?

[mstrpln03]

I was thinking of using 2-13 watt cfl "daylight bulbs" on a 6x8 scrubber to start and then switching over to an LED array at around 3k. I think I will use 1/2 watt or 1 watt, as opposed to 3 watt LED's. My reasoning is I can get a broader light spread with more of the lower wattage diodes then I can with a couple of 3 watt Led's, at such a close distance.

I was wondering if anyone has done this. I would like to know how many red/white diodes would I need to get 3k. I would like to know a little more about drivers and power supplies as well.

Any input would be greatly appreciated.

Thanks

[rygh]

Feel free to peruse and join the "Modern LED scrubber light" thread. It seems to be taking on a life of its own, and
has some the data you probably want.

People have done LEDs, yes, with some success, but nothing great yet.
There have been a lot of failures. So I strongly suggest you get CFL working first, then be prepared to tinker.

A combo CFL/LED is not a bad idea.

From personal experience, light spread and distribution is not a problem with 3W LEDs.
I have checked it with a light meter and various builds. And you can always add diffusion plate.
Those small LEDs are a pain. Far less efficient, a lot of soldering, and problems attaching heat sinks.

[Gigaah]

I think I know about where your at in the understanding of light Kelvein(K) and color(in nm). Also the graph I pieced together between a few different ones should demonstrate to you What a white LED really is. Its a modified blue LED so to speak. White is not a color. its a mixture of colors that create a white light. the more blue it has the higher the Kelvin rating the more red/yellow it has the lower the Kelvin rating. Not to mention that one..say red led is not the same as the next. slightly different red(nm) as well as lumen output per watt. The blessing and curse of LED's is that at a given color it has such a narrow but highly intense spike at such a specific nm range that you have to be sure your putting out light in exactly the right nm range for what you want or you can get poor results.
These 3 are all WHITE from warm to cool.
[attachment=2:1k15zc1j]White LED profiles.jpg[/attachment:1k15zc1j]

Here is a white and also shows the narrow range the colored LED occupy
[attachment=1:1k15zc1j]Color LED profiles and white.jpg[/attachment:1k15zc1j]

A low Kelvin warm white CFL may have the same color as a similar warm white LED. But the CFL's light is spread more widely(and less intensely) including in ranges we believe do not promote growth in plant matter.

Here is an example of a "full spectrum daylight T5 flourecent bulb" in the 6000k range
[attachment=0:1k15zc1j]midday.gif[/attachment:1k15zc1j]


I hope this is of some help.

[waucedah_joe]

My first scrubber, which I considered a proof of concept, was undersized but all I could fit under the tank. It was open air, lights were clamp on fixtures using CFL twist bulbs. When I started it up I quit dosing sugar and stopped using my skimmer (it broke). Even at that it kept my nitrates in check for 3 months until I had a pump failure when I was out of town and the scrubber algae mostly died. It was messy and hard to remove for cleaning. However, it sold me on the concept so I decided to build the "ultimate".

This is rather overkill for my 75g but I made it with my pending 140g build in mind. I used two 50 watt light panels with the red and blue LEDs. My first DIY with acrylic and I was surprised at how easy it is to work with.

One thing to note my screen retaining method. I cut 2 slices from an end cap and notched them to make a "C". They slip over the header pipe and rotate through holes cut in the screen to hold it up. To remove the screen one just rotates the rings so the open part is down and the screen drops down. Way better than ty-raps and I don't have to take the end cap off to slide the screen out.

I did build this just before your new design came out and frankly I'm not sure I'd recommend the LED's. They work fine but they're expensive and fairly large 12"x12". I had to mount them about 3" from the screen so I didn't have little circles of light. And I'm not sure about the benefit of the red and blue since the light doesn't mix at that distance. Pretty sure they are designed to grow other green plants at a greater distance.

I'm feeding it with the full flow of a Quiet One 2200 which at 2' of head is about 500 GPH.

Enough talk, here's the pictures

First the retaining rings. You can also see one of the threaded light mounting blocks.

http://i143.photobucket.com/albums/r132/waucedah_joe/Scrubber/72273f87.jpg

Here's one without the lights mounted getting ready for the flow test at the laundry tub. You can see one of the light panels on the left. Try to ignore all the background clutter. :)

http://i143.photobucket.com/albums/r132/waucedah_joe/Scrubber/cb372423.jpg

And finally, here it is installed. It's so bright I had to make a cover for it since I run the lights opposite my DT lights. In the new 140g. build, support equipment like this will be behind a wall.

http://i143.photobucket.com/albums/r132/waucedah_joe/Scrubber/201847dd.jpg

This thing works. When my prototype crashed my nitrates got up to 25 ppm before I was able to get this online and in 3 weeks they were near non detect level with the Salifert test kit.

[inkidu]

Joe, if you don't mind telling me, what led did you use?

Thanks for any help.

[SantaMonica]

These are the 40 or 50 watts panels that I recommend. Two of them is 100 watts, good for a 100 square inch screen.

[inkidu]

You recommended led? Wow

Only experimentally I hope.

What is the brand etc...?

[waucedah_joe]

"You recommended led? Wow
Only experimentally I hope. "

What am I missing here?

These are the lights I used.

http://cgi.ebay.com/50-WATTS-LED-GROW-L ... 35a75a68df (http://cgi.ebay.com/50-WATTS-LED-GROW-LIGHT-PANEL-RED-BLUE-UFO-HYDROPONIC_W0QQitemZ230440986847QQcmdZViewItemQQpt ZLH_DefaultDomain_0?hash=item35a75a68df)

[rygh]

Great to see another LED success!!
Nice system.
Any pictures of the growth?

The color seems similar to mine. A little lighter red, as expected. Of course very hard to tell with a camera.

Those LED panels you bought seem pretty good. I think they are the best purchasable ones I have seen so far.
The negatives (Not meant in a bad way):
- They use the smaller 5mm LEDs, so are not nearly as power efficient, and do not last as long.
- Who knows what sort of power supply they used. Can make a big difference in longevity.
- Those 55W panels are probably about the same as a 30W panel that uses state of the art LEDs.

But sure saves a LOT of hassle by buying them instead of DIY. A HUGE win there.
Those built/shipped panels are about the same price as just the high-power-led components, so I think price is a win as well.
Light distribution will be about the same. There are many more 5mm LEDs than for the ones using high power, but the angle is tighter. Ends up similar / slightly better.

Only thought is that you may want to paint the outside of the box white. Everywhere except for windows onto the screen.
Recover some of the wasted light on the side, plus shield your pipe from light. Less growth in the slot.

[waucedah_joe]

Actually the bulbs on these LED panels are 8mm. Not shown in the photos is my custom cover to block the light from the DT since it's on a reverse light cycle. The reason there's no pictures of the cover is that it's made from a computer desk chair box. :D Agree on the need for a light shield for the header pipe although the mninimal growth that I get in that area is easily cleaned off. I'll copy a post I made on another forum that shows the cleaning process as well as growth.

[waucedah_joe]

Step by step cleaning. This took me 15 minutes including taking the pictures. (More than twice that to do this post)

Take off the lid.
http://i143.photobucket.com/albums/r132/waucedah_joe/Scrubber/Scrubber%20Cleaning/CleaningScrubber_001.jpg

Retaining rings engaged.
http://i143.photobucket.com/albums/r132/waucedah_joe/Scrubber/Scrubber%20Cleaning/CleaningScrubber_002.jpg

Disengage retaining rings, screen drops from slot in header.
http://i143.photobucket.com/albums/r132/waucedah_joe/Scrubber/Scrubber%20Cleaning/CleaningScrubber_003.jpg

Unscrew union to free header for removal.
http://i143.photobucket.com/albums/r132/waucedah_joe/Scrubber/Scrubber%20Cleaning/CleaningScrubber_004.jpg

Screen and header in the bucket.
http://i143.photobucket.com/albums/r132/waucedah_joe/Scrubber/Scrubber%20Cleaning/CleaningScrubber_006.jpg

Dirty header.
http://i143.photobucket.com/albums/r132/waucedah_joe/Scrubber/Scrubber%20Cleaning/CleaningScrubber_007.jpg

Header cleaned with scrub brush.
http://i143.photobucket.com/albums/r132/waucedah_joe/Scrubber/Scrubber%20Cleaning/CleaningScrubber_008.jpg

Dirty Screen.
http://i143.photobucket.com/albums/r132/waucedah_joe/Scrubber/Scrubber%20Cleaning/CleaningScrubber_009.jpg

Cleaning screen with plastic putty knife. Thick algae comes off in a sheet.
http://i143.photobucket.com/albums/r132/waucedah_joe/Scrubber/Scrubber%20Cleaning/CleaningScrubber_010.jpg

Algae scraped off.
http://i143.photobucket.com/albums/r132/waucedah_joe/Scrubber/Scrubber%20Cleaning/CleaningScrubber_011.jpg

Yummy. For scale, I can palm a basketball with my thumb and ring finger.
http://i143.photobucket.com/albums/r132/waucedah_joe/Scrubber/Scrubber%20Cleaning/CleaningScrubber_012.jpg

Clean screen after scrubbing with a brush then rinsing.
http://i143.photobucket.com/albums/r132/waucedah_joe/Scrubber/Scrubber%20Cleaning/CleaningScrubber_013.jpg

Close-up of holes in screen for retaining rings.
http://i143.photobucket.com/albums/r132/waucedah_joe/Scrubber/Scrubber%20Cleaning/CleaningScrubber_014.jpg

Nutrient export!
http://i143.photobucket.com/albums/r132/waucedah_joe/Scrubber/Scrubber%20Cleaning/CleaningScrubber_015.jpg

[rygh]

Great build, great growth.
Jealousy setting in. Time for me to give up on horizontal, just pay for the extra pump, and build a vertical.


Actually the bulbs on these LED panels are 8mm.
Aha, then I take back what I said about longevity. (But not efficiency)
The newer 8mm advertise a very long life.

Minor suggestion: Make 2 more rings, a bit like the clips for the screen, and glue them on each end of the pipe, just inside the Plexiglas.
That keeps water from running along the pipe and creeping out the ends. Not usually a problem, unless you forget to clean well and the
water comes out the top overflow holes. From experience.

[SantaMonica]

Yes it will be good to get the first "successful" led scrubber: Two months of non-measureable N and P, with the scrubber being the only filter.

[waucedah_joe]

OK here's the test results to date. All tests are with Salifert Nitrate test kit. Wasn't until I decided to get parallel results with the newly bought test kit that I noticed the one I had been using had expired over a year ago. So, results before 4/17 were with an expired test kit and results after were with a new test kit.

1/21/10 - new scrubber installed
2/27/10 - cut scrubber lights back to 12 hours.
4/4/10 - scrubber lights back to 18 hours.
4/17/10 - new nitrate test kit.

Nitrates
1/24 - 25
1/30 - 10
2/14 - 5
2/20 - 2.2
2/27 - <0.5
3/7 - 2.5
3/14 - 2.5
3/21 - 2.5
3/28 - 2.5
4/4 - 5
4/11 - 2.5
4/17 - 2.5 (old kit) - <0.5 (new kit)
5/2 - <0.5
5/9 - <0.5
5/16 - <0.5

[SantaMonica]

Looking good. If you could do a P test too, that would be great. For N tests, I like to look through the side... helps show any pink that you might miss from the top.

[waucedah_joe]

The Phosphate test kit I have is at least 3 years old so I doubt the results would be meaningful. As for the Nitrate test I always figured (maybe wrongly) that anything under 1 is good so I never worried about the more sensitive test. I can start doing what you suggest for future tests though if you think that will help with the discussion.

[whites]

wow love it!

Do you think your scrubber could be wider and taller? and if so by how far do you think?

The led looks like it has good spread on the sides as the growth looks pretty good on all the edges.

I still havent set mine up yet and looking into the square now.

My Contact can make 310x310x46 @ 45w with colours in these ranges, I Can also specify ratios!
blue 440-470
red 620-670
orange 610-15
white 4500-8000k

What range and ratio do you think I should go?

[whites]

Also you said you wouldnt recommed them (led) they seem to be doing the job, do you still feel the same?

Do you think the distance from the screen is still a huge deal? can the panel be moved closer?

Cheers

[waucedah_joe]

The reason I said I wouldn't recommend the LED solution is two fold. The LED fixtures are not inexpensive and I first looked at them thinking, LED -> low energy consumption. Well I'm using 100 watts of LED so for that much juice you could have a whole lot of CF's. The other reason I think flourescents might be a better choice in some applications is that my ATS is so tall I can't use the overflow as a source of water because there's not enough space between the top of the sump and the DT for it to fit, so I have to use another pump. There's another 35 watts on top of the LED's. All that said, I am going to build another one. I've got a buyer lined up for the one pictured above. I'm also in the process of setting up another tank. I built the stand 40" tall for this one so I think I can squeeze the ATS in and use the DT overflow as a water source.

As to the size of the unit. I'm actually going to make the next one shorter and narrower. The Algae only grows thick directly in front of the panel. The panel is 12"x12" and good growth is only about 13"x13". It's green out to the sides but there's very little growth at the edges. Where the algae grows thick I scrape it off in a thick sheet with a plastic putty knife. Everywhere else I have to use a scrub brush.

Light distance from the screen. I think if you wanted to grow more algae I would actually move the lights away from the screen farther. The light would spread farther and you might gain another 1" or so around the edges, maybe getting to an effective area of 14"x14". If you move the lights in any closer than what I have them you get a bunch of circles of light with no overlap. I decided on the distance I used by moving the lights away from a sheet of paper until there were no gaps between the circles of light that the LED's produce. That's all really hard to see in a photo because the light is so intense it saturates the picture.

[rygh]

Cost analysis:
You have a 2x50W system that will probably last 7 years, costing roughly $180.
So 180/7 = $25 per year.
The 7 years will vary depending on quality of components though, which is hard to estimate.
Assuming standard T5 bulbs, you need 4, replaced every 3 months (1/4 year), at about $4.50 each.
So 4*4*4.5 = $72 per year.
And you still need to pay for a CFL/T5 fixture, and ballasts give out as well. Say $100 over 15 years.
So 100/15 = $7
Clearly the LED is cheaper long term.

Lighting Power:
Yes, you are burning about the same power as a good T5 unit. The reason is, you are using the lower efficiency LEDs.
If you were using more modern ones, it cuts power about in half. (More often more. I don't have exact specs on your LEDs)
So you COULD be saving 50W.
That 50W * 16 hrs * 265 days / 1000 * CA rate of of $0.26/khw = $75 per year.

SO LED COULD SAVE UP TO $129 PER YEAR.
And that is a conservative estimate, assuming you have high quality components.

[whites]

great thanks for that, maybe putting them further out? Id be interested to see how far they could be set back. maybe having lower wattage at the distance you have might be ok too?

any one with an idea on color range??

[waucedah_joe]

Thanks rygh, I hadn't considered bulb refreshing in the equation, good to know.

whites, I've wondered the same thing myself about how far away they'd be effective, or if I could have used lower power lights.

[rygh]

I think the general consensus on best algae color = blue + deep red.
Distance = as close as possible, as long as light distribution is good.
For me, about 5 inches.

Have to plug the long led thread : viewtopic.php?f=3&t=435 (http://www.algaescrubber.net/forums/viewtopic.php?f=3&t=435)

[whites]

I guess if mine are 45w then we will find out.

Could you post what dimensions your box is expecially how wide, really want to know the distance of one side of the canvas to the inside of the cantainers side. I think your design would suit my set up, Id paint the ends in white to reflect some more light on the ends and also wouldnt need the leg/stand you have to fit it under the tank. Anything else you would tweak?

By looking at the growth looks like the light could go back at least an inch or even two I dont think there would be much light drop off at that distance.

Maybe a bigger gague pipe with a section cut out so it could slip over the pipe with slots to help stop light getting to it and stop algea blocking.

[waucedah_joe]

Dimensions:

The inside of the box is 4-1/2"d X 17"w X 19-1/2"h. The top, sides, and bottom are 1/4" Lexan. The front and back faces are whatever Home Depot sells that's close to 1/4", something like .23" or .22". The lights are mounted to 1/2" blocks (2-1/4" pieces laminated together) that are drilled, tapped, and glued to the front and rear panels. Since the lights protrude from the front rim of the fixture they are only about 1/8" away from the Lexan. So, the lights are approximately 2-1/2" from the plastic canvas. They are so intense that I think they could be moved farther from the screen, however at some point I'm sure that the illuminated area gained by increasing the distance to the screen becomes a trade off for slower algae growth.

[ocean rock]

its a nice build . the light might even get you in the mood for love with a bit of Barry white on in the back ground , :lol:

[inkidu]

"You recommended led? Wow
Only experimentally I hope. "

What am I missing here?

These are the lights I used.

http://cgi.ebay.com/50-WATTS-LED-GROW-L ... 35a75a68df (http://cgi.ebay.com/50-WATTS-LED-GROW-LIGHT-PANEL-RED-BLUE-UFO-HYDROPONIC_W0QQitemZ230440986847QQcmdZViewItemQQpt ZLH_DefaultDomain_0?hash=item35a75a68df)


Sarcasm.

I never knew SM to talk up LED too much. No offense SM.

Its encouraging to see people having success with LED.

I will be curious to see how well those panels age.

The "teardrop" LED have a great deal of epoxy (lens material) which tends to darken i.e. they dim.

Although the better LED (cree for ex.) have additives in the epoxy to help counteract this.

Best of luck.

[rygh]

The newer teardrop LEDs have a very long advertised lifetime. Like 100,000 hours on some.
My guess : They have fixed any lens issues, and since they are lower power, the lower temperature
allows for longer life.

BTW: My LED DIY box:
Simply made of wood, painted white inside. 30" x 6.6", and about 6" from the screen.
There is a 1/16" layer of diamond diffusion grating on the ATS itself. (For new one, going to simple clear 1/16" acrylic)

[inkidu]

The newer teardrop LEDs have a very long advertised lifetime. Like 100,000 hours on some.
My guess : They have fixed any lens issues, and since they are lower power, the lower temperature
allows for longer life

How long a led lasts and how bright they are after some use are two different things.

I am only mentioning this because I have read what other people have posted about how these type of lights dim.

People at least as far as I can tell have the equipment to test these things.

Personally I have no first hand experience with them ("teardrop LED") and don't get me wrong I hope they last a long time.

I think that the main benefit from LED (considering there expense) use is that they last so long.

Hope this helps.

[whites]

hey there any updates? how is the design going? any new pics of growth you can post?

Cheers

[whites]

any new pics? what is your tank up too? how are the leds?

[waucedah_joe]

I know this is an old thread but I haven't been on here in a while and thought I'd check in with an update. I sold my first LED scrubber to a fellow reefer that was having problems with algae in his main tank. I built another that was nearly identical but had 45W panels instead of the 50w panels on the original. Not a lot of research just bought the cheapest ones I could find. Anyway, I started the current scrubber up along with my upgrade from a 75g to a 140g display in June of 2010. Except for the initial spike upon start-up my nitrates are zero with the Salifert test, I don't test for phosphates. I've never done a proper water change. I do add fresh salt water to replace what I pull out when siphoning sediment out of the sump but that adds up to no more than 5 gallons every 2-3 months. I see from reading newer threads that this is all old school but I couldn't be happier with the results. Here's some pictures from June 2010 first and then today.

Left Side
http://i143.photobucket.com/albums/r132/waucedah_joe/140%20Build/Startup_004.jpg

Middle
http://i143.photobucket.com/albums/r132/waucedah_joe/140%20Build/Startup_005.jpg

Right Side
http://i143.photobucket.com/albums/r132/waucedah_joe/140%20Build/Startup_006.jpg

FTS
http://i143.photobucket.com/albums/r132/waucedah_joe/140%20Build/Startup_007.jpg

and now
Left Side
http://i143.photobucket.com/albums/r132/waucedah_joe/140%20Build/LeftSide_2-20-12.jpg

Middle
http://i143.photobucket.com/albums/r132/waucedah_joe/140%20Build/Mid_2-20-12.jpg

Right Side
http://i143.photobucket.com/albums/r132/waucedah_joe/140%20Build/RightSide_2-20-12.jpg

FTS
http://i143.photobucket.com/albums/r132/waucedah_joe/140%20Build/FTS_2-20-12-1.jpg

[SantaMonica]

Nice!

PBR has a nice home. Seems like lots of coralline.

[Floyd R Turbo]

Nice looking system! I was trying to find this thread last week, I'm glad you revived it. Do you have a link to the panel that you bought? Does it use 1W LEDs? Also a pic of the scrubber would be cool.

[waucedah_joe]

Nice!

PBR has a nice home. Seems like lots of coralline.

PBR?? Sorry, I'm usually pretty good with TLAs (Three Letter Acronyms) but somehow Pabst Blue Ribbon just doesn't seem to fit.


Floyd,

I'll take some pictures when I get home this evening. Is there anything in particular you'd like to see on the scrubber? Pretty much like the first one I built other than I added a couple of light shields to the lid to keep algae from growing too close to the distribution pipe. As for the lights, I'll see what I can find. Bought them almost 2 years ago so not sure if I've got any info or not. I do remember that I didn't like them as much as the 50w panels I had on the first scrubber. The 50w panels had an external power supply similar to a laptop while these have an internal PS. Given the choice I'd rather keep the 110vac away from water, although it hasn't caused any problems to date.

[SantaMonica]

I meant PBT, powder brown tang.

[Floyd R Turbo]

Someone put PBR in a freshwater tank during a party in high school. The fish were swimming kinda funny the next day. I wouldn't recommend it.

[waucedah_joe]

Ah, PBT, yes it seems happy. Hippo Tang is passing him up in size now. Was commiserating with a friend who just lost his job and watching my Red Wings loose to the Black Hawks. Anyway, too many beers to make a post last night. So, here are the pics of the scrubber.

Front
http://i143.photobucket.com/albums/r132/waucedah_joe/140%20Build/DSCN0433.jpg

Back
http://i143.photobucket.com/albums/r132/waucedah_joe/140%20Build/DSCN0434.jpg

Lid with light shield.
http://i143.photobucket.com/albums/r132/waucedah_joe/140%20Build/DSCN0435.jpg

Top down
http://i143.photobucket.com/albums/r132/waucedah_joe/140%20Build/DSCN0436.jpg

Lights on
http://i143.photobucket.com/albums/r132/waucedah_joe/140%20Build/DSCN0437.jpg

[kotlec]

How are your LEDs cooled ? It seems to me like your heat sinks are covered, when I look at photos.

[waucedah_joe]

These panels were purchased as is, not assembled by me. There is no heat sink. LED's are soldered directly to a PCB. They are low watt and don't generate much heat. These are similar to what I have but I don't think the ratio of reds to blues is as high on mine.

http://www.ebay.com/itm/45w-112-LED-Plant-Grow-Light-Panel-Red-Blue-/250986999876?pt=LH_DefaultDomain_0&hash=item3a6ffdb044

Just a couple of thoughts. I replaced my screens when they were about a year old. They were getting smooth and being covered with coralline algae. This spring they were getting in the same shape and I just roughed one up with the hole saw again. That worked well. I’m going to do the other screen in a week or two. I also noticed thick calcium deposits on the back sides of the screens which I scraped off.

The other thing one might notice is coral growth in the DT is not outstanding. Actually the tank has made a remarkable comeback from a two pronged disaster. About a year ago I purchased a new LED fixture from Auraled (google it if you want the story on that). The day I put the new fixture on the tank I also replaced the tubing on my peristaltic two part dosing pump. Long story short, I cut the tubes too long and overnight a full gallon of part 1 and part 2 siphoned into the sump overnight. When I got up the water looked like skim milk. Because of that I left the underpowered LED lights on the DT way too long, blaming my coral decline on the chemistry upset. After two months I went back to my 6x54w T5 lighting and things have been doing much better since.

[Floyd R Turbo]

Thanks for posting the pics. As far as LED panel arrays go, that's probably one of the better ones I've seen. Most of them like that are 225 LEDs and 14W so they're all way under powered. Next time I see someone posting a link to one of those, I'll point them to this one.

For non-forced cooling stock fixtures, this is a pretty good one. I think the wattage is a bit on the low side overall, but that is made up by the use of bandwidth, it's about a 3.5:1 red:blue ratio which is probably a little high on the blue, and interstingly enough, this is a "B" band fixture. It uses 630nm Reds and 460nm Blues. Most "grow" lights use 660/460 which is a mix of A and B. So congrats, you're the first one I can recall using this bandwidth!

Going by the new sizing and light guidelines, I don't think many people would be in the market to use this light though because not many have a need for a 12x12 screen (12 cubes/day) and if you were feeding that much, it would probably overpower the screen, just because there's not quite enough intensity. This is a very good example however of the usefulness of LED lighting on a screen that is too large for the feeding (I'm assuming here that you're not feeding 10 cubes/day or more). CFL and T5HO screens that are too large compared to feeding tend to grow yellow rubbery algae like mine currently is. So far, all the LED builds I've seen tend not to grow the yellow algae at all, which I find very interesting.

Thanks for posting that info!!

[waucedah_joe]

Just so there's no confusion, the lights that I posted the link to are NOT the lights that I bought. I meerly posted that to show what my lights looked like because someone was asking about a heat sink. Mine were purchased long enough ago that the listing is no longer on eBay and the seller I got them from does not sell grow lights anymore. Mine came packaged in a plain white box, like generic cigaretts, no instructions, no documentation, I have no idea what wavelength the LEDs are. I did look at to see that the ratio of red to blue is 3-1. The LEDs are encapsulated in plastic that is 8mm diameter.

At peak production, I was removing 2c of algae from it every week. Now it has dropped to about 1c per week. I was getting a yellow band in the middle of the screen due to poor flow distribution. Over time the PVC pipe has warped and closed up the slot in the middle. I've been opening it up a little at a time with an angle grinder and cutting wheel when I've got it apart for cleaning. Looks pretty good now.

I think I'm going to start feeding more since I've obviously got capacity that is not being used. I make my own frozen food and form it in ice "cube" trays that make a long cylinder shape to fit in a water bottle. Once frozen I cut them in half and feed one of those halves per day. Pretty close to 3 of the comercial sized cubes. My blue hippo tang is starting to get aggressive during feeding and I'm wondering if he needs more food to be happy. I had another blue hippo tang that was a big teddy bear and never bothered anyone but when he got to be about 9" I felt he had outgrown my 75gal., so I traded him to a LFS.