The Contentious Issues of Lighting

[itiwhetu]

I just turned them back on today and the highest I will have it go to is 40% brightness

I don't understand how these new lights work. I'm used to having one tube or two tubes. 40% brightness, 40% of what?

 

[Naughts]

I don't understand how these new lights work. I'm used to having one tube or two tubes. 40% brightness, 40% of what?

40% intensity. They dim the lighting.

 

[itiwhetu]

40% intensity. They dim the lighting.

What is 100% in Lumens

 

[Colin_T]

Manufacturers seem to assume that the brighter is the better

But where in the world do you get cloudless skies each and every day and no obstruction tween ground or water and the sun

Nowhere.

Over the ocean, various rivers, creeks and streams all around the world. Australia has lots of waterways with few to no trees growing along the banks. Even in places like the Amazon, the actual river won't have trees shading the entire surface. There will be patches of trees shading sections of water but also large tracts that don't have any shade during the middle of the day. Obviously in the morning and afternoon, the trees provide shade because the sun is on an angle, but during the middle of the day, it's lots of light for the fish.


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@itiwhetu 's setup is a bit different because he is getting more light from the side, so he throws a cog into the mix, but it is interesting in that the front of the tank is the dark side, and that is where the fish are in his photo.

They could also be there for food because that is where they normally get fed.


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Those of you with brightly lit tanks how often do you see your nocturnal fish? How often do you see your fish just cruising, rather than swimming up and down your tank?

I didn't keep nocturnal fish in brightly lit tanks. My diurnal fishes (mostly rainbows and barbs) would be out in the open acting naturally with all lights on the tank.

 

[Deleted member 149562]

Can I just clarify something regarding the great outdoors.

Granted there are some hot and sunny places.....I have been lucky to have been to Saudi Arabia, Oman, UAE, Yemen, Brazil, Argentina and India where cloudless blue skies and baking sun are quite frequent.

However there is maybe less than a handful of places that have totally cloudless blue skies and baking sun 365 days a year without fail.

What I am trying to say, and what seems to be misinterpreted, is that the lights supplied with an aquarium are extremely bright, piercing bright and they are relentless.

The sun moves in the sky...a bright aquarium light is fixed

As the sun moves it can throw shade via the landscape throughout the daylight hours, so there will always be a slither of shade in which fish can go to

An aquarium light stays put and does not give the same effect that the sun does, the fish have no peace from it, it is relentless, it doesn't get shaded by clouds, it doesn't dip behind landscape...it is there above them for as long as the human has it turned on......floating plants cannot replicate the sunrise or the sunset nor can they replicate a cloudy day...the light is full volume all the time.

Which is why swapping out to a light that can be dimmed or using theatrical film over the light can dial things down and make it more natural. If, like me, you have a remote controlled light that can be infinitely dimmed or brightened, then you can really go for the cloudy day, cloudless day, storm clouds...even a sunrise and sunset. By changing the light intensity and changing from a harsh white to a greyish light you can replicate closer and the fish react to that in incredible ways. The theatrical film give that effect ability cheaply and easily without replacing the entire light for one like mine.

Think of it as a human having a bright light shone direct at you compared to a warmer, softer light in the corner of the room...the light in your face is intimidating, it is uncomfortable whereas the warmer, softer light in the corner relaxes you and makes you feel comfortable and cozy.

 

[Back in the fold]

I have lights on only two of my seven tanks. I have Java Fern Microsorium pteropus that is doing just fine with room light only from a north facing window. I took all the drapery off that window. As @itiwhetu says , my fish cruise around placidly rather than dart about like lunatic asylum escapees. I've heard it many times on this forum that most fish are forest fish that hide in the shadows.

 

[Colin_T]

A lot of the new LED light units have dimers and you can adjust the light colour and intensity throughout the day. So they can easily be made to replicate daylight by ramping the light up slowly over a few hours in the morning, and reducing it in the evening. You can't do that with fluorescent lights, which are becoming obsolete and are being replaced by more efficient LED lights.

 

[itiwhetu]

A lot of the new LED light units have dimers and you can adjust the light colour and intensity throughout the day. So they can easily be made to replicate daylight by ramping the light up slowly over a few hours in the morning, and reducing it in the evening. You can't do that with fluorescent lights, which are becoming obsolete and are being replaced by more efficient LED lights.

How do you know, how and when to change the intensity, how do you figure out the correct intensities? I believe that just creates too many variables, how can you figure out how to change the intensities and times to fix a problem, considering you have these lights changing continuously all day.

 

[Colin_T]

You replicate the sun light. In the morning we get yellow light, then red, then blue, then ultraviolet (UV). In the afternoon the UV goes first, then the blue goes, then the red goes and finally the yellow goes.

Peak times for blue and UV light is between 9am-4pm.
Peak times for red and yellow light is between 7am-6pm.

A lot of LED light units can increase or decrease light intensity in 25% increments. In the morning you have yellow light come on and 30-60 minutes later add a bit of red. Add blue an hour after that, and UV an hour after the blue (if you are using UV on a marine tank). UV isn't necessary on freshwater tanks but can be used if you don't have any bottom dwelling fishes or albino fishes.
In the afternoon/ evening, you reverse the process and reduce blue, then red, then yellow light.

When the lights are on you can increase the intensity by 25% every hour. The red and yellow light reach 100% before blue. And blue is reduced before red, which is reduced before yellow.

If you don't have many live plants in the tank or light sensitive fishes, only take the light intensity up to 75% instead of 100%.