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isenhart
06-29-2015, 02:13 PM
I have a small, 21 gallon tank I made from a larger broken tank. For filtration I'm using an under gravel filter with lava rock for biological and mechanical filtration.

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Instead of using tubes to pull water from under the gravel, I made some fiberglass boxes. I used a 2x4 for a mold, so it measure 3.5" x 1.5".

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Then I added 660 red, 3w, leds, and covered them with more fiberglass resin for waterproofing. There's a pair of boxes, one has 5 lights in it, the other has 10. The one with 10 I have attached to a dimmer.

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Here it is installed in the tank. There's a big nursery housing some fry that blocks the view other one, so there's no picture.

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I tried using string to for the algae to grow on, it didn't work. The string got all tangled up and disintegrated. So I replaced it with some of the black knitting mesh that was roughed up.

I was paranoid about how hot the led's got in such a small tank. I didn't want to overheat the water and kill the fish. So I started off with 1 box light with 5 lights only. The box seemed to be a total bust. There was black algae all over the glass but the inside of the box was pretty much completely void of anything.

With no appreciable change in water temperature I then added the second 10 led box with the dimmer turned almost off, ~10% output. Now I can do head to head comparisons at the same time. I didn't keep a good log of the time frame, but around 4 weeks later... the box with 5 lights running at 100% had some promise.

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A week after that, my first harvest.

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Not a ton of growth, but I have a pretty large dual screens and only 5 small fish and a couple of fry. The entire screen is green, there just isn't much that's long enough to pull off.

I was a bit surprised at how much red light came through the fiberglass. With no light coming from it, you certainly can't see though it. The light spilling out has a lot of growth on the tank. My plan is to coat it with something to trap the light and make it less of an eyesore in the tank. I didn't want to get that involved in it until I knew that it would actually grow algae. So now that I know it works, I'll have to do some more refinement. I also turned up the box with 10 led's from 10% to 100% output, I'll have to wait and see if 15W or 30W of light grows more algae.

So far, I'm very pleased. I have a small tank that is completely free from anything hanging off the sides or top. Once I get the algae scrubbers disguised better I will have a very clean natural looking tank. Instead of a mess of plumbing and equipment, in the tank or hidden in a sump, that I really don't want.

SantaMonica
06-29-2015, 08:21 PM
Very nice. You could tuck it away in a fake rock or stump.

Strings are not as good in FW, as you saw.

bluelobstor
06-30-2015, 07:33 AM
When the tank is done where is the scrubber going to be?

isenhart
07-01-2015, 04:29 PM
It will be in the back corners of the tank. I made them with slip on pvc fittings so I can just slide them out to clean them. I still need to route the air line into the base instead of the scrubber so it's easier to remove.

bluelobstor
07-02-2015, 04:35 PM
If I understand correctly you are running a ugf with the scrubbers providing the flow through the filter? Is there any way you can coat the box that holds the scrubber white to reflect the light back and to keep it from the rest of the tank?

isenhart
07-08-2015, 06:59 AM
Here's a picture of them installed on the tank with lid off.

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Update, I ran both uas at 100% power. One with 5 lights for 15 watts, the other with 10 lights for 30 watts.


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30 watts must be too much light, there is very little growth and a lot of it is pure white. The 15 watts is growing well, but to be fair it was much better established. Though, the bulk of the grown is away from the lights. I'm not sure if that's because there is too much light, or not enough air on the other side?

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I guess I'll turn the 30 watt side down to 50% and see how it looks next week.

bluelobstor
07-08-2015, 11:38 AM
Great thing about being dimmable is you can dial the light in just right.

isenhart
07-22-2015, 02:43 PM
Well after two weeks I took my scrubbers out.

The 15 watt is slowly going in.
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The 30 watt is working better turned down to ~50% output. The algae is green instead of white now.
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Neither one is very thick. I was thinking that I over sized the amount of screen area I need, and would need to make it smaller. Two things come to mind for me.

The first is that due to the "transparency" of fiberglass there is quiet a bit of green algae growing on the glass and gravel near the boxes. It's not growing very fast, but is apparently finding enough light and nutrient to at least sustain itself. I'm sure the scrubber would grow better if no light escaped. So I'm trying a black 2 part epoxy that I'm using to coat the outside, hopefully that will trap the light and kill off the surrounding algae.

The second thing that comes to mind is so what? Right now there is enough screen area for the algae to spread out and grow slowly, and it appears to be healthy green algae. At the current rate of growth, I estimate that I would only have to clean out the scrubbers about every 3-4 weeks.

Here's the tetra easy test strip results.
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The results speak for them self. I should note that in the last 4 weeks, I've done two water changes of ~4 gallons each. The last one was over a week ago. Probably next weekend I'll add the fry to the main tank and clean the algae off the glass and gravel.

Until the next update.

SantaMonica
07-22-2015, 03:34 PM
I think the screen will fill in after you scrape it all off down to the white.

isenhart
07-22-2015, 04:46 PM
Thanks for the suggestion, easy enough to test I guess.

isenhart
07-30-2015, 03:01 PM
Before resetting the tank up last week I covered the 15 watt scrubber with JB weld. To my surprise, light still comes through. It's not as much, but it's certainly not catching all the light. I also took out the fry nursery and cleaned any algae, green and brown, from the display tank.

The 30 watt scrubber filled in a lot.
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I completely scraped the 15 watt scrubber, and this is what grew back this week.
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What's interesting is the growth is on the opposite the side where the lights are. It makes me wonder if 15 watts of leds is too bright still.

Even though in the scrubber the algae looks really slimy, and it is, but when it breaks off and floats around the tank it looks more like hair. Lots breaks off when I removed the scrubber for cleaning.
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Here's a picture of the tank.
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Another with the scrubber lights on.
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I still need to do something about the light and aesthetics now that I know they do the job of growing algae.

SantaMonica
07-30-2015, 03:24 PM
FW algae is very slimey and thin hairs. And 15 watts of LED on one area is quite a bit.

isenhart
08-26-2015, 09:15 AM
Well I went on vacation for 2 weeks. It ended up being almost 3 weeks since the last scrubber clean out. The fish had an automatic feeder that was overfeeding them, I'm not sure there would have been this much growth if I had been hand feeding them.

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The only downside is quiet a bit of the algae broke off from the scrubber and floated into the tank. It did come right off with a gravel vacuum attached to a small power head, so it definitely wasn't attached to or growing on the rocks. I also wiped down all the glass with a white paper towel, and only little bit of brown algae came off. I think most of it was growing on the silicone in the corners.

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The tank has been set up for almost 6 months. It's been nearly 8 weeks since there has been a water change in my 21 gallon tank with 8, 2" fish in it. The only filters I'm running is the lava rock and the algae scrubbers that pull water from under the gravel. The fish are healthy and active, and the water parameters you can see for yourself.

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I'd say the scrubbers are a success and I'm pretty happy with the setup. The only complaint I have is that the red light comes through the fiberglass. I'm thinking about redoing the up tubes with a ~2-3" black abs pipe that will contain the light.

SantaMonica
08-27-2015, 05:32 PM
Good work.

isenhart
08-27-2015, 10:39 PM
No sir, good work to you. You were the pioneer, all I did was read up and reinvent the wheel you created. Thank you for your help.

isenhart
08-31-2015, 09:31 AM
Doing my weekly clean up. This is what the fresh water algae looks like still in the water. At this point, there is almost as much algae growing on the fiberglass as there is on the screen.

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isenhart
01-16-2016, 11:08 PM
Long term update.

I painted the scrubbers with the black spray paint for plastic. That worked really well to contain the glow.

I also removed the 15 watt scrubber. I didn't have the bio load to need two scrubbers and the lower power one never really took off.

The algae that grows now looks nothing like the green hair algae in the previous post. Its very dense and grows almost exclusively on the fiberglass right next to each light. The knitting mesh used to be completely covered with algae, now it's reduced back to just a few patches right in front of the lights. It makes me wonder about the previously believed best distance for spacing the light from the screen. It would appear that anything more than about 1/2 the size of a quarter from the light will eventually be starved out and have no light, at least in my scrubber anyway.

I'm still very happy with the algae and lava rock as a sole filter source. It was almost 6 months since a water change with 11 fish ~2-3" in length for a ~21 gallon tank. The only thing I didn't like was the substrate (lava rocks) was fairly large. I lost several fry that went down in rocks never to return. It also trapped some detritus below the filter that apparently wasn't a problem for the water quality, but it was impossible to get at without taking down the whole tank. If I do another one, I'd use ~3" black abs pipe for the scrubbers, and either break the lava rock into smaller pieces or use some other type of small rock.

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A few weeks ago I took the tank down. I have decided to try a salt water tank. I didn't want to have air bubbles causing salt creep, so I've done a redesign. Stay tuned for an update on my in tank waterfall scrubber next.

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SantaMonica
01-17-2016, 11:47 AM
When you removed the larger scrubber, the remaining nutrients were high for the remaining scrubber and thus grew darker slime. This darker slime blocked the light quicker, and formed rings.

With the waterfall, you'll still need to protect was salt spray where the water drains down.