Sunlight no not the dishwashing one..

7 May 2007
Reaction score
Guys I saw a article on a tank in Seattle where 1/2 the tank was under sunlight and the other used our normal lighting MH & T5's.

The coral growth in the sunlight half was almost double than under lights. Now we all know Seattle isn't renowned for its bright sunny days.

I want to try lighting a section of my new 3m with sunlight. Has anyone tried it and what should I look out for. I'll maybe balance the light with some T5's for nighttime viewing.
I feel sunlight is more beneficial than we realize and i wouldn`t be surprised at a doubling in coral growth due to the exposure to it.
I have always wanted to do this. Please keep this thread updated copper. Is your setup close to a window or do you have some other clever plan?
I have a clever plan Gali, its right up there next to taking over the world. The "minister of finance and happy relationships" wants a sky light in the dining room. The units I looked at has a single call it "entry point" on the roof and then with mirrors you can direct the light to a couple of rooms. The idea is to have a sunlight "hood" over the tank.
Can't wait for some pics. When's the sunroof going in?
i'll do the roof a few days before the tank building starts, who ever is going to build will prolly want to build on site as i won't be forming part of the 3x1 carring the @#$%! tank party
My only concern would be heat and possibly guy's living in places like Seatle can get away with it. African summers get hot.
There is no denying that Natural sunlight is the best option, when last did you see a natural reef with Halides hanging over them..

CB it's defineatly worth considering. Just make provision for a Chiller that can cope with the concentrated sunlight being fed into your tank.
Colour can be offset with actinic artificial lighting.
lekker when are you starting with your new project?
I tried this a couple of years ago. Went back to Halides after it wasn't providing enough light.

I think you need at least an 800mm diameter tube to replace a 250mm halide. So be careful of splitting up your source too much.

I will be doing this again with my new tank, only with a full 1.2m x2.5m skylight above the tank.

I will be filtering the light with a blue filter to get out some of the yellow and red light as unfiltered sunlight is a little yellow.

I will no doubt be fighting a lot of heat but hope to beat it.
BB, you can get the untreated domes.

So what domes we actually talking bout here? :whistling: sorry the blonde in me does come out once in a while :lol:

sounds like bad case of confusion to me... :y10:
I have used direct and indirect sunlight on my coral holding tanks for years. As it is from a large window I do have to have artificial lighting for when the sun has moved over. I can confidently say that I get much better results from sunlight. However in the first year algae battles turn into algae wars, as the lower Kelvin light will turn even the smallest amount of nutrients into cow fodder. However once the system is well matured your corals will benefit greatly from the strong light.
I have an Apogee Quantum light meter, which will give me a reading of about 120 to 160 under the halides but jumps to 750 to 950 when the direct sunlight falls on the exact same place. Make you think hay?
I think i am going to go into the sky light business after this thread.

Hi Copperband go for it.
I have seen an amazing aquarium in Dbn which gets limited sunlight through a window. The lamps he is using are simple T8's, nothing to write home about! However he gets afternoon sun. No algae, hard and soft corals doing very well. I have as a result setup my own 6' which gets about 2 hours sunlight a day. Have started putting in corals I have had for some time under T5 lighting.
The T8 lamps are one 4' Phillips actinic and two 4 ' Aquarelle's.
Oh by the way I am using a Jebo skimmer on it.

Day one: Taken at 9 am before sunlight.

Last edited:
I think i am going to go into the sky light business after this thread.

:lol: I also plan on making use of skylights soon. The ones that swivel 90 degrees to open. So the result would be 100% unadulterated sunlight. The other benefit,... would allow the hot humid air to escape. When a slight breeze blows, the amount of air that gets channelled through them is amazing; especially if windows and doors are open elsewhere in the house.

Currently have them in my bathroom. Each skylight measures 1m x 0.5m. I will also be filtering certain wave-lenghts.

The disadvantages.... heat as mentioned....and viewing hours. In summer the sun comes up at just after 4.... and in my planned setup the first direct rays should hit the water at 6.00am. So by the time you get home from work, its lights out. Bummer.
im sure you could still run the hailides as a supplement in the evenings for a while......whats the point of having a tank that is dictated by lighting hours not viewable by the owner who"s spending his lifes savings on it? id alter the lighting for my benefit....
Last edited:
Top Bottom