Sunlight or No Sunlight

[C-21 USAF]

I've got a 150 reef that is by a large window and I like to let the sunlight in for about half the day. I'd say about 20% of the tank actually gets the direct sunbeams that you can see penetrating the water. As the sun passes over many different sections of the tank get covered at different times.

Is having no sunlight an "old school" way of thinking back when there was no margin of error in reefing?

Does it have a place in today's reef tanks?

Thoughts?

 

[usefulidiot213]

I know there are fellow reefers, who supplement their large tanks with natural sunlight. I think it's funny that people say don't put the tank were it can get sun light, when we spend thousands of dollars on lighting that's used to replicate the sun.. :thumbsup:

 

[redfishsc]

+1^^^

The only issue you may have is that algae growth tends to favor the low color temp of natural sunlight.

That being said, it's free light .


Just watch your tank temps.

 

[captstinky]

I like natural light. But I'm also on a tight budget.

 

[flyyyguy]

I have a pull down curtain for the sides of one of my tanks to prevent it.

to be sure, it isnt because I think its bad, its because the bright sun would hit that tank early in the morning.......then go fairly dark again before my photoperiod starts at noon. So I dont want it becasue it doesnt work with the tanks schedule.

 

[hk855]

My tank is by a window and gets indirect sunlight for most of the day, mostly on one side. I have knowticed that that side of the tank gets the brown diatoms built up faster on the glass. Its nothing uncontrolable, I just need to clean the glass more often and probably should reduce my VSV dosing to help prevent it. Also my tank is only 6 weeks old so its still going through some nut flux.

 

[billford]

i have a 125g that sits in front of 3 southfacing windows.i love it.no big difference with algae.the only thing i would plan for is the summer temp.i have a200g sump in the basement that helps.

 

[strendo]

My tank is by a window and has a skylight over it. The corals love it, once you eliminate nitrates and phosphates algae shouldn't be an issue

 

[sharrison]

Sunlight coming into your tank is going to be filtered by the glass. There would be little benefit, if any at all. You would more than likely get brown crap and nuisance algae in your tank.

That is what I've experienced, myself. Once I moved all my tanks away from any windows. The problem stopped. I also do not put anything between my bulbs and the water because of the filtration of the light, including any kind of shield. I prefer retros.

 

[tmz]

Big windows and a skylight near my display tanks. Corals seem to love it.

 

[jtrasap]

I've got a great big window, facing to the east, right next to my 180. It gets tons of sun in the morning, and I've never had an algae problem. As long as you keep nutrient levels under control, you should never have an algae problem.

 

[flyingphish]

free light is right!

 

[Rickyrooz1]

My tank receives indirect sunlight. It's good for the corals growing on the sides of the tank.

 

[C.Ton9187]

sweet placement and setup.

 

[frankpayne32]

+1^^^

The only issue you may have is that algae growth tends to favor the low color temp of natural sunlight.

That being said, it's free light .


Just watch your tank temps.

Is there evidence to support this? That nuisance algae prefers the ~6500K lighting of natural sunlight? I have heard both sides of this and am very curious. I don't see how algae could grow more if there is natural sunlight added. With all the PAR that we are adding to the tanks via our lighting systems the limiting factor for nuisance algae growth should be nutrient levels, not the addition of "natural" light. Just curious.

 

[becact]

Remember also, folks, that the sunlight hitting your tanks is not the same as the sunlight on the reefs. When the sun has to pass through many meters of water on a reef, certain frequencies are filtered (the longer ones first, ie; reds and oranges), and the color temperature changes. Sunlight hitting your tank is certainly a different color than sunlight that reaches corals on reefs.

It is proven that certain color temperatures (~6500K) promote macro algae growth, but I'm sure this would pass on to nuisance algae. See melev's site for his experiment with different temps of fuge lights while growing chaeto.

 

[frankpayne32]

Remember also, folks, that the sunlight hitting your tanks is not the same as the sunlight on the reefs. When the sun has to pass through many meters of water on a reef, certain frequencies are filtered (the longer ones first, ie; reds and oranges), and the color temperature changes. Sunlight hitting your tank is certainly a different color than sunlight that reaches corals on reefs.

It is proven that certain color temperatures (~6500K) promote macro algae growth, but I'm sure this would pass on to nuisance algae. See melev's site for his experiment with different temps of fuge lights while growing chaeto.

Agreed with your above points, but doesn't that ~6500K light promote growth in all photosynthetic organisms not just macro/nusiance algae? From what I understand, growth from 6500K metal halides provides explosive coral growth but the colors aren't exceptional, kind of what is seen on a wild reef.

 

[becact]

Agreed with your above points, but doesn't that ~6500K light promote growth in all photosynthetic organisms not just macro/nusiance algae? From what I understand, growth from 6500K metal halides provides explosive coral growth but the colors aren't exceptional, kind of what is seen on a wild reef.

I don't know enough about it to tell you one way or the other. I thought peak PAR for corals was around 460nm (quite blue), though maybe I'm wrong on that point. I know the 10k halides providing better growth is an old adage indeed, but I think recent advancements in lamps may negate that benefit. Again, I could be wrong.

Also, I would think that corals would have evolved to grow the best with the temp of light available to them under water, which is probably closer to 10-14k. Certainly macros, which mostly grow in the shallows, can make use of yellow light better than corals, which evolved under deeper water.

 

[Toddrtrex]

Twice a year, for about a month each time, the sun coming through my skylight hits one of my tanks. Never have any increased algae growth during that time, and the tank just looks incredible -- the part that gets the sunlight. Heck, I wish the sun hit the tank year round.

 

[tmz]

Where is it proven that nisance agae faovrs 6500k. Is there a link to reference?