Direct Sunlight

[DanSReef]

Hi Everyone. I thought I would ask a quick question on Direct Sunlight for Reef Tanks!

In the past I thought the rule of thumb has been that direct sunlight is generally not a good thing for fish tanks….it encourages nuisance algae. I am curious how many folks on the board here get direct sunlight to their tanks….and the potential pitfalls.

When I set up my tank initially, I thought that direct, yet filtered light would be really the exception and not the norm for my tank. I have come to find out that there currently is a 45 min time slot where the light is just at the right place to bathe my reef tank in sunlight. I noticed this yesterday while I was working from home. Here are a couple of pictures of the tank.

What is interesting….it seemed the tank just exploded in activity...and came to life during that time.... I noticed more “bugs”, I noticed incredible color of corals, I noticed that the fish got into…. almost a mode of soaking up the sun. I have a cleaner wrasse that seemed to kick his maintenance of the tank inhabitants into high gear…. It was pretty interesting to watch.

Anyway, I am curious of other thoughts, feedback and direction here. Should I eliminate the direct sunlight? Should I limit it? Should I allow it to continue?

FYI..... for lighting in the tank... I am running T-5 HO lighting…. Daylights and Actinics.

 

[smkndrgn142]

my tank does get partial sunlight during the day and I find that it's a good thing. Other than making me clean the glass a little more often, I've seen nothing but benefits. The corals in the area seem to grow like crazy!

 

[Tahoe Reefer]

I've got more than one tank in my living room that get more than an hour a day of direct sunlight a day. I dont have any algae blooms or other problems associated with the sunlight. My leather tank really fluffs up in the sunlight, the corals are very happy in the sunlight.

 

[Frankie]

There are few pro's and con's to direct sunlight.
Keep in mind, even the shallow reefs in the oceans are deeper under water then what our aquariums allow. Most start at 20 feet! These depths allows filtration of ultra violet radiation.
Nutrients are what cause algae to thrive. In a low nutrient aquarium direct sunlight can be very beneficial. It is a natural source of food for photosynthetic animals.
If your going to utilize direct sunlight though, your going to want it to enter through the top of the aquarium not the side. Allowing it to enter through the side will have a negative effect on the benthic organisms living under the rocks and corals. Without this life your aquarium can crash.

 

[DanSReef]

What is interesting....this slot of time has been happening...for many months now... and so is essentially routine. I just never really saw it before as I am not around at the time of day typically. So...I think the tank has settled nicely….and to smkndrgn142’s point… I clean the glass little more often that’s all.

Frankie….to your point… One interesting this is that I had window films installed on these windows a few years ago and they block out 99% of UV. The rooms used to bake in the Summer Sun. Now…. I do not need to close blinds, shades or adjust the thermostat. There is literally very little UV and Heat associated with the light. So, perhaps that is providing the filtration of the sunlight as you refer to from deeper water that can be simulated in an aquarium environment. Interesting….

I appreciate the thoughts here. My intent here is to learn and share…. Thanks for the comments thus far. Keep them coming.

 

[smkndrgn142]

Keep in mind, even the shallow reefs in the oceans are deeper under water then what our aquariums allow. Most start at 20 feet! These depths allows filtration of ultra violet radiation.

I've been on reefs in Fiji and in Belize and neither of them started at 20 feet below the surface...there were parts I couldn't swim over because they were so shallow. The water didn't get much deeper than 20 feet in Fiji until you hit a drop off.

 

[map95003]

A friend of mine has a DIY 800 g tank that sits in his green house. It's lit with nothing but the sun. He grows all sort of corals fast, however the color isn't there.