Light spectrum for corals AND macroalgae?

[LordJoshaeus]

Hi everyone! I was going to add macroalgae to one of my reef jars, but when I did a little research and asked around I learned that the 20000k spectrum of my light over my reef jars would likely not grow macroalgae very well. Thus, my question is this; is there a "happy medium spectrum" where both corals AND macroalgae will grow well? My mom may get a proper saltwater tank in the future and I would love to put both corals and macroalgae in it. Thank you

 

[ISpeakForTheSeas]

Hi everyone! I was going to add macroalgae to one of my reef jars, but when I did a little research and asked around I learned that the 20000k spectrum of my light over my reef jars would likely not grow macroalgae very well. Thus, my question is this; is there a "happy medium spectrum" where both corals AND macroalgae will grow well? My mom may get a proper saltwater tank in the future and I would love to put both corals and macroalgae in it. Thank you

In layman's terms, the Kelvin rating (20000K in this case) tells us (in theory - in practice the vendors are rarely honest with this rating) the color the light appears to our eyes to be - that's important for looks/aesthetics, but not really for any photosynthetic organisms (like corals and algae) in our tanks; all it really tells us is that it looks very deep blue in color to us.

A happy medium for corals and algae would likely be a full-spectrum, bluish leaning white light (bluish-white by spectrum/wavelength, not necessarily Kelvin).

So, you would want a light with a good, blue-heavy full-spectrum, and the ability to put out a good amount of PAR:

Do you know the specific light model of the LED's?

If you do, you may be able to find the Spectral Power Distribution Chart/Graph (shows basically how much of each color of light is produced by the fixture) and PPFD Chart (basically a map of the PAR output of the fixture).

Also, despite popular statements to the contrary, algae can grow just fine under blue light - it just isn't generally ideal for viewing the algae (with some fluorescent exceptions).