Most microalgae can use and thrives in blue spectra too - the difference is that you will not see them as well as you do in more natural lights. My point is that photosynthetic corals need more light than most of the algae we do not want need. The reason why I mentioned nutrients is that you - IMO - can´t starve away microalgae either from energy (light) or nutrients and keep your photosynthetic corals in good conditions. The secret with CUC is to introduce them before you see any algae in the tank. These type of algae have a doubling rate below 24 hours. It means - if you have 1 mg microalgae day 1, you have 2 mg day two, 4 mg day 3, 8 mg day 4, 18 mg day 5 and so on. You should introduce your CUC as early as possible - when will mos of the reproduction biomass convert to food every day. Today - there are a lot of small. very good hermis suitable for nano aquarium, snails too.
By myself - I have has success with a more than one 20 L Nano tanks there I use direct sunlight as a complement to rather bad lighting (Back around 2006 when the only option was compact fluorescent lamps and often more daylight than blue light) This was mostly soft corals nano.
Yes - ip looks like you have more control with artificial light but in the end of the day - you need to turn that up in enough intensity to have your algae to thrive
Sincerely Lasse
