Are 2 smaller lights better than 1 big light?

[HAAAAAAAA]

I had a thought, is one big light better than 2 smaller spread out lights? For example
Is one big 40 watt bulb better than two spread out 20 watt bulbs or is it the opposite?

 

[Spare time]

One bigger light (such as a hydra 32) packs more punch per a given area but the smaller lights (such as one AI prime / half of the hydra 32) will spread the power to a wider area though with less intensity per a given area as a tradeoff. Which is better depends on the size of tank and your budget.

 

[Olefreebe]

Given it produces same intensity and just general output I would think 2 is better. Same light produced with better spread and less shadow. Just my opinion tho.

 

[twentyleagues]

Obviously 2 lights spread the light more but usually at the cost of total output as @Spare time has said. Take Radions for example one xr30 puts out more par than 2 xr15s in the same area but the 2 xr15s will cover a larger area.

 

[HAAAAAAAA]

I currently have some macro algae in my display and wanted to move it down to a 60 gallon sump which is about 14 inch height compared to my display which is 30 inches high so instead of the 40 watt bulb I have on my display i wanted to use about 2 15 or 20 watt bulbs spread out

 

[twentyleagues]

I currently have some macro algae in my display and wanted to move it down to a 60 gallon sump which is about 14 inch height compared to my display which is 30 inches high so instead of the 40 watt bulb I have on my display i wanted to use about 2 15 or 20 watt bulbs spread out

Lower output better spread. But with the difference in how much closer the lights will be I am sure it will be fine.