Direct Sunlight into our tanks good/bad?

[Vagabond]

My tank is set up in a room with a west facing window, so for about the last 2 hours before sunset I can flood my tank with sunlight. It is very cool to see all the corals lit up with natural light.

Anybody else out there allow direct natural light into their tanks?

Wanted to know if there are any negative effects/dangers from doing this or conversely any benefits ?

[kellehar]

I have the same thing with my tank and im the same as you I dont know if its good or bad but my anemone's seem to like it as well as the fish. the anemone's will turn into to the sun at that time and the fish will all go to that side of the tank when the sun shines through. at first i thought may be it was to cold or somthing like that but checked the temp and alls well. so if you get an awnser i'd also like to know the results

Thanks
Justin

[Beverly]

Two of our three tanks are against east facing windows. Whenever the sun shines directly on them, I keep the blinds closed so they don't heat up. If your tanks don't heat up from the late evening sun, I don't see a problem letting the sun shine on them. JMO.

[OCDP]

I thought natural sunlight that hits a reef causes algae problems??? Thought I read it somewhere (on reefcentral)

[Beverly]

After the sun has passed and doesn't shine directly through the windows, I often open the blinds. Have never had extra algae problems from doing that. I think if there is going to be algae problems, there would have to be excess nutrients to fuel the algae growth. Best to keep nutrient levels very low.

[EmilyB]

I'm not anal about tank cleaning so the natural sunlight does cause more algae growth, imo.

I just got a new chevron to enjoy that surplus !

[Doug]

I would say that if sunlight is causing algae, then its because ofthe nutrients in the tank, not the light itself. I once had a tank that recieved lots of sun in the morning. I had a 250w Iwaski bulb that was drowned out by the sun. Aside from a bit more algae film on the glass, not many other problems.

My corals use to love it and they always seemd to expand even more. I would suppose tank size has something to do it also. Over heating in a smaller tank is easily possible from sunlight, so that must be watched.

Its also like putting 400w halides over a tank that been running on low lighting with no algae. If nutrient levels are high, they stay in check with lower lighting but increase the lighting and instant green.

[meltdownaverted]

From what I've heard, the glass from the window and from the tank will block most of the beneficial wavelengths of light. So although it may look brighter, I don't think it will help your corals. IF you have an algea problem it can only make it worse. Just pay attention to how your tank reacts and decide from there.

[doublette]

One of my freshwater tanks gets the late afternoon sun. I was always told it would cause major algae problems, but it hasn't. The plants in the tank have grown like weeds since it's been getting the extra sunlight. I would think that a saltwater tank would be the same way, if your nutrients are in check then it shouldn't be a problem. Just my opinion.

[danny zubot]

I actually use the indirect sunlight for dawn/dusk lighting in my tank. I no longer use actinics, not sure what I'll do in the winter though.