Neptune Aquatics

Vindicated! BRSTV investigates fuge lights!

sfsuphysics said:
While that seems to make sense on the surface if everything is equal, the problem is by judging the setups behind him when they're talking... they did make everything equal and that in itself might lead you to some wrong conclusions of what you might need to successfully use macro algae as a nutrient export.

What do I mean? Just look at the setups, how deep are those fuges? At about 1:40 of the video you get a good cross section shot, and you can see the fuges are in fact a reasonable fuge height compared to the size of the tank. But one thing that, IMHO, is not reasonable is the height of the fuge light, it's at the same height as the tank light, now this doesn't provide incredibly insightful results because yeah no duh a more powerful light will put more light energy into the tank than a less powerful light at the same height above the tank, and guess what things that use that light energy to grow will in fact grow faster including algae (ignoring spectral responses to keep things easy).

Drop that light down to 1/2 the height so it's right off the surface of the water just like the light is that is over the main tank and you increase the total light energy by a factor of 3-4 (4 theoretically in a vacuum, but the air/water interface will reduce that a bit more), if you look at a paused frame of the same time code I mention above you'll see the cheap CFL bulb has MAJOR light spillage at that height, it illuminates the back tank/fuge/sump contraption they do the testing in fairly well, so if you drop that down to half it's height a lot of that steep angle stuff probably would be reflected back into the tank and actually end up helping grow that chaeto.

So yeah, more power will grow chaeto faster, that much is undeniable, especially considering how much higher the algae's light saturation levels are compared to say corals. So again no shock that that 90W LED absolutely blew away the 15W LED with directional output and the 23W CFL multidirectional output bulb with a "reflector" of it. But if you take that 15W LED and drop it by to half the height, you might get similar results to a 45W LED, or about half the H380. So that might be able out compete the tank LED you have especially since Kessil's "H" series is specifically tuned for horticulture.
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Except if I also lower the light on the H380 then we are back to square 1.


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To me it looks like all the lights are about the same height. Probably done intentionally to get a true idea of their potency relative to each other.
 
They are, and I'm sure the thought was "It doesn't matter the height actually is since we're doing apples to apples" and in that sense I agree.

I'm just saying people coming to the conclusion that you need a really high watt light to compete against your tank lights might be jumping to the wrong conclusions. Since you could potentially lower the light to get more energy out of it hitting your fuge algae.

I haven't really thought too much further in it, but it could also be a matter of the H380 lamp is just an absolutely super beast too, it could be overkill lighting for chaeto. They used pH as a metric for showing how effective the light is, and having your pH jump by 0.7 points simply due to a ball of chaeto might even make me think that it's too much of a good thing
 
sfsuphysics said:
They are, and I'm sure the thought was "It doesn't matter the height actually is since we're doing apples to apples" and in that sense I agree.

I'm just saying people coming to the conclusion that you need a really high watt light to compete against your tank lights might be jumping to the wrong conclusions. Since you could potentially lower the light to get more energy out of it hitting your fuge algae.

I haven't really thought too much further in it, but it could also be a matter of the H380 lamp is just an absolutely super beast too, it could be overkill lighting for chaeto. They used pH as a metric for showing how effective the light is, and having your pH jump by 0.7 points simply due to a ball of chaeto might even make me think that it's too much of a good thing
Click to expand...

Getting the light closer would undoubtedly lessen the amount of wattage needed. This is the whole premis with an algae scrubber.

The H380I is probably too much light for their test system. In a larger system like the brs 160 it would probably match up nicely. I think I heard him say that the PAR on it was 1600. The light itself is also just one part of the equation. How long it's on, and how much chaeto will also influence its effectiveness. So maybe with a higher wattage light you just don't run it as long or you keep a larger amount of chaeto to get the results you're looking for.
 
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