Since we have an incredible algae expert on the forum, I thought this article was interesting. The article is about growing better tomatoes but they did the original testing on algae. I had no idea that algae and other plants had to expend energy to reject the wavelengths of light that were not helpful or even stressful to them. in this article if they only presented the ideal light wavelengths to plants they grew better as they were in their 'sweetspot' for wavelength.

I was wondering if there was some way to turn that in reverse and use some sort of light filtering to expose the algae to the 'stressful' wavelengths to inhibit their growth which would also help us not rely so much on chemicals. Obviously this would be best suited for indoor aquaponic organizations where the light source could be filtered or altered more easily. But perhaps there could be a way through a pond cover or a lensing system to alter the characteristics of the light at the surface boundary of the water.

Algae and light