LED scrubber for a 120g reef tank

[Floyd R Turbo]

So you're really going to be feeding 12 cubes/day?

I'm not sure what the calculator says, but my personal guideline is one 660nm Deep Red LED on each side of each 2x2 section of screen, placed 2" from the screen with a diffuser at 1". That would be the maximum density. Minimum density would be one on each side of every 4x4 section of screen.

For a 144 sq in screen, that equates to 36 reds on each side maximum, and 9 on each side minimum. So 12 LEDs per side would be about right.

What I do for the arrangement is just put the reds on a square/rectangular grid, at 2" on center. Then, I place the half-power blues in the middle of those squares. not at every one.

Here's a pic of my L4 fixture



That's for a screen that is ~13" wide and ~4" tall, one on each side

[molabecirovic]

I guess a sheet of nori per day makes a huge difference... i do feed a sheet of nori a day which is 72 sq/in, without the nori the calculation goes down to about 70sq/ in screen. also I am counting for 5 cubes a day and 3ml of coral food (phytoplancton, oysterfeest...).... all together comes to 157sq/inches. I figured my 144 screen should most likely do just fine than.

Based in your picture the blues are connected in parallel and everything else is in series, so the blues are more or less as one led as they share the power? what is the benefit of having the blues? If i do only reds, would that be wrong?


Thanks again in your comments

[Floyd R Turbo]

Yes the blues are essentially one LED, at least as far as the driver sees it (power wise). The result is that the combined output of 2 half-power blues is actually more than a single full power one, because LED get more efficient as you dim them. But for our purposes that's really negligible.

I do not count the blues into the overall "watts per sq in" calculation either. I consider them supplemental. The reds are the primary growth source.

You do not need the blues. But IMO they help. Some that added them in after running only reds noticed that growth appeared to become "sturdier" for lack of a better term.

[SantaMonica]

1 cc is about 3 grams of food.

I'd use less blues.

1 cube is probably ok for 2 clowns. Don't really need to feed the softies.

[molabecirovic]

Here is the scrubber temporally running on CFL bulbs (4x 43w with homedepot reflectors) until I get the led fixtures ready. I removed the small scrubber (8x8) section and left and only the larger side running (18x8). I need to change to led's soon the CFL's are releasing a lot of heat.

[rygh]

Looking like a lot better mix of screen area/lighting! I think it will work a lot better.

Ideal would be to cut the middle out of that tank, and glue the sides back together.
So your new tank would only be about 6 inches wide. 3 inches on each side of screen.
With all lighting external, away from water.
It is not that hard to do that with a table saw.

For LED, instead of red+blue, consider "deep red" + "warm white".
I have been switching.
If you look at the spectrum of a warm white LED, there is a big spike of blue, then
it fills in a wide range of the upper spectrum.
If you look at specific ideal red wavelengths, the deeper red seems better.
So with the combination, you get it all.
Optimized deep red. Extra blue from the warm white.
Wide high end spectrum from the warm white.
But everyone has different ideas on what is the best LED.

[Floyd R Turbo]

I'm going to be testing this eventually. I think there may be some truth to this, but the intensity of anything outside of the deep red and violet LEDs is much greater, which is why I run the blues at 1/2 power. Same might go for WWs.

I would like to find out if there is any added benefit to re-inserting the "wasted bandwidth" as I have been calling it. Since switching to LEDs, and having over 100 units in the field with that mixture, I haven't seen anyone reporting that they have thick, yellow, rubbery growth, as I used to get all the time under broad-spectrum 2700K T5HO. This led me to think that the bandwidth between red and blue was somehow used differently and contributed to this type of growth. If it comes back under WW 2700K, that would be interesting.

[rygh]

I'm going to be testing this eventually. I think there may be some truth to this, but the intensity of anything outside of the deep red and violet LEDs is much greater, which is why I run the blues at 1/2 power. Same might go for WWs.

I would like to find out if there is any added benefit to re-inserting the "wasted bandwidth" as I have been calling it. Since switching to LEDs, and having over 100 units in the field with that mixture, I haven't seen anyone reporting that they have thick, yellow, rubbery growth, as I used to get all the time under broad-spectrum 2700K T5HO. This led me to think that the bandwidth between red and blue was somehow used differently and contributed to this type of growth. If it comes back under WW 2700K, that would be interesting.

Yes, you really have to wonder. I wish I had time for more experimentation like before.
(For discussion I included the old chlorophyll spectrum that includes the various cartinoids)
Those extra spectra may in fact help the wrong type of algae.

I run some warm whites, and no issues with yellow algae. But the red is far stronger.

My guess : It probably does not matter much, as long as you hit a decent overall intensity, and have a lot of red.
Warm whites are super cheap, so that may be a factor if nothing else.

[molabecirovic]

Well the Led's are done and running. This is the configuration I ended up using. I used 660 deep reds and 460 royal blues at 1/2 power.


here are some pictures of the installed lights



I covered the tank with mirrors and aluminum tape as the red light is pretty strong and makes my closet look like a photography dark room ...

[Floyd R Turbo]

Perfect! Nice LED build!