I've just stumbled upon this very interesting article on what the ideal level of light for an aquarium is according to the aquascapes of Takashi Amano. World-renowned aquascaper and founder of the Aqua Design Amano (ADA) contest and sponsoring company, Amano has published several books of his aquascapes and given light levels along with almost every aquascape. Using this information, John Fitch has not only discovered that Amano uses more light per gallon on smaller tanks, but has also developed a calculator to determine, using the data from Amano's tanks, roughly what light level Amano would be likely use on your aquarium. The calculator can be found in the article, which is called "Lighting as a Function of Tank Size in the Aquaria of Takashi Amano."This is further evidence against the Watts per Gallon rule, which was always just a rough guide. In other words, 40 watts over a 10 gallon tank may seem like a lot of light (4WPG), but in fact, it should have closer to 65 watts. The reason for this is due to surface area, but exactly why I haven't quite gotten a handle on yet, so I'll do more research and report back when I have a better idea. All I know is that smaller tanks demand more light per volume and larger tanks demand less. The WPG rule holds for the most part in medium sized tanks (about 29 gallons to 55 gallons), but below and above that, it's better to go by something like this tool, or do your own calculations using surface area (-gulp-). Personally, I like the tool...
It's interesting to see that someone has analyzed the light levels this way. I feel, however, that this falls short of what we need to in order to get a basic idea of light levels. You must take into account depth as well as area. A 110X is the equivalent of a 90g aquarium in footprint, but is deeper. Anyone that works with plants under lights knows that light levels fall off repidly with distance, especially when water enters the picture. Also, I think that basing your lighting on wattage is the wrong approach. A watt is a measure of energy consumption, it does not indicate the light levels you can expect from a bulb. Everyone knows that flourescent bulbs' light levels diminish over time, but they still draw the same wattage. Using lux or lumens would be a better approach.
ReplyDeleteI know this is an old post, but I have an idea on why many get away just fine using the WPG rule on smaller tanks vs higher light levels over the smaller tanks. It's the distance of the light from the water. It's a growing trend to have your tank unhooded, hence you need extra light to penetrate down to the bottom.
ReplyDeleteI think I have just scared myself... I am planning on doing a 8ft x 4ft (wide) x 2ft planted tank, going on surface area that is going to be a lot of light...
ReplyDeleteThanks for the article and link.