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Sunlight

4K views 21 replies 13 participants last post by  Anon 
#1 ·
I have always been led to believe that one should avoid natural sunlight hitting the tank but I have never really questioned it.

I thought that the reasoning was that there was a likelihood of an an increase in algae.

This confuses me since our artificial lighting is meant to mimic the natural spectrum.

Is the idea just that one loses control over how much light the tank gets or are there other factors?

Thanks!
 
#2 ·
I have always been led to believe that one should avoid natural sunlight hitting the tank but I have never really questioned it.

I thought that the reasoning was that there was a likelihood of an an increase in algae.

This confuses me since our artificial lighting is meant to mimic the natural spectrum.

Is the idea just that one loses control over how much light the tank gets or are there other factors?

Thanks!

Personally, yes it's the random light variations that is the main issue. as well as at times underestimating intensity..
Our lights look bright but normally there is no comparison, even w/ indirect sunlight.


Of course latitude/season/tank orientation all matter.
 
#13 ·
Hi Immortal1

The spectrum shown on your Seneye is very odd. Lots of blue, lots of red but very little mid-band. I don't have a midday spectrum that I can easily upload right now. May I suggest you look at the following:

https://en.wikipedia.org/wiki/Sunlight

The above (Wikipedia) spectrum is very similar to the one I obtain from my budget spectrometer. Please scroll down the Wikipedia page until you get to this: Spectral composition of sunlight at Earth's surface

Anon
 
#8 ·
I have a plastic 10G I use to raise daphnia in and it gets bits of sunlight in the mornings at this time of year here in Northernish Scotland. It is definitely brighter than the light in the tank and the daphnia congregate in the sunlight either because it actually grows algae in the water or they are programmed to assume it. But they respond. Its light through vertical blinds so stripes move across the tank.
 
#9 ·
I always believed natural sunlight + aquarium was not a good idea, however at this time of year my open top aquarium gets about 3 hours of full sun, so far without an outbreak of algae . I think if it was for several hours it might cause a big problem. Time will tell I guess !
 

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#10 · (Edited)
My 4 year experiment with keeping and growing semitropical fish in a planted trough outside in cloudy Oregon has come to it's close.

I initially had to grow lots of floating Water Hyacinth, to effectively shade the submerged plants but the bio-load of the fish wasn't sufficient enough to keep the plants growing well. At the end, last years Fall, and this year's Winter and Spring had me using a worn silver tarp over the entire tank with a lot of 2" diameter holes cut into it to mimic light coming through a tree canopy. There was a lot of healthy Salvinia to moderate these little spots of sunlight.

I still had some algae problems, but the tank has been pretty good with low and moderate light plants. My big Java Ferns were pretty vigorous. Since everything in that tank has moved to a smaller 80 gallon trough inside a greenhouse, I have better control over the light.

Years ago I had a 45 gallon and 32 gallon that were my first "planted tanks", that in addition to their Mercury vapor lamps, got about 1~2 hours of indirect sunlight reflected off our linoleum floor every morning when it was partial to full sun. I was growing Chain Swords, E. Hormanii, Starweed, Rotala Rotundifolia and Macrandra, and Poly Hygro in these tanks without issue, The Java Mosses and Ferns also were very vigorous
 
#11 ·
I have several small shrimp Bowls hanged by my west facing windows that get 4 to 5 hour afternoon sunlight. The bowls are heavily covered with floating plants (frogbit, salvia and duckweed) and guppy grass, dwarf hair grass or dwarf saggitaria. It’s a zero tech set up with no heater, filter or aeration, only sunlight to drive plant growth, light feeding of shrimp, and monthly WC top with dirty water from my big fish tank to replenish nutrients. I measured big fluctuation of temperature (65 to 87F diurnal change)and pH (7.2 to 8.7) pre and post sunlight period due to direct sunlight and depletion of CO2. Shrimp can tolerate the fluctuations and are thriving. Floaters grow fast but submerged plants grow slowly due to CO2 limitation, including stem plants that hardly grow at all. With help of snails and cherry shrimp, water and glass are clear and free of algae except spirogyra which I remove with a tweezer every couple week. Spirogyra is easy to remove but hard to eliminate as it always returns and I can’t use Algaefix as it will kill shrimp.
 

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#12 ·
Thanks for these posts. I am debating placement of a new 25 gallon Landen rimless tank setup and the lighting has me in analysis paralysis.

Looking for low to mid light for, at least initially, a low tech tank. I need dim-ability and sunrise and sunset effect. I do not need other bells and whistles like "thunderstorm".

I just want happy plants in a pleasing tank! I have accomplished this previously when there were fewer choices. Jungle look is OK but not big on the stylized look.
 
#14 ·
I'll try to upload a blue sky spectrum that I obtained in August last year mid-morning here in Old Blighty. Bear with me as I'm not on here very often.

Success!

Anon
 

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#15 · (Edited)
FYI @Anon - the thick black line is what the Seneye is seeing. The colored graph behind it is just a colored back ground for some sort of reference. From what I can see on my Seneye, the highest level is around the 640 to 650nm. The Seneye does not record specific spikes, but more of an average. With that said, it does mimic your blue sky spectrum to a degree. The Seneye does not seem to "see" the spectrum above 720nm
"The useful range for color vision in humans, for example, is approximately 450–650 nm" from Wikipedia link.

 
#20 ·
Hi Immortal1

Thanks for that. Now it makes much more sense. I used to have a Seneye about 7 or 8 years ago but I was so disappointed with it that I made a pact with myself never to buy another.

Looking again at your Seneye spectrum, its response in the red wavelengths is not bad, is it? Blue is where its response isn't so good. Since chlorophyll a peak absorption occurs at 430nm and 662nm, the Seneye would be reading roughly 50% down at 430nm. I think it's perfectly fair that it doesn't see anything above 700nm as that is the top end of the visible and PAR bands. Once we get into wavelengths above 700nm, we are into the infra-red.

Anon
 
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#21 ·
Seneye is bad with violet not blue. It actually reads blue like it should and reads about 10% hot on red. 430nm is in the violet spectrum. Chloro A peak absorption occurs at 660nm and 420nm while Chloro B peak absorption is 450nm. It is very bad with violet like most are although the new Apogee fixed a lot of it since reefers push violet instead of red for Chloro A because it can penetrate deeper in the water.
 
#22 ·
Seneye is bad with violet not blue.
Absolutely correct. I tend not to discriminate between them when, in practice, it probably makes no difference. But, thanks for pointing out my error. For the record, 380-450nm is violet, 450-485nm is blue.

Anon
 
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