We frequently get questions about bulb color choices and where to put each color bulb in the fixture. The good news is there is a ton of flexibility in the answer. Let’s go over a few of these things and hopefully make some sense of it all.
Bulb color combinations:
The best way to pick your bulb choice if possible is matching an aquarium you have seen. The color of the aquarium lighting is a very personal choice. Trying to pick a combination for “the best growth” or “the best color” will leave you spinning your wheels with opinions and blanket statements that may or may not have any truth to them. If you aren’t sure what you like, it’s often a good idea to buy a few extra bulbs so you can mix and match them to get the color you most desire. The growth and coloration of the corals will follow if the corals other needs are met such as water flow, water quality etc. As always, if you’re putting new bulbs in a dimmable fixture, make sure you burn them in properly.
Fixture channels:
ATI light fixtures are designed with 2 channels. One channel has 2 bulbs, and the other channel has the remaining bulbs (2, 4 or 6 depending on if it is a 4, 6 or 8 bulb unit respectively). Typically channel 1 is used for a dusk and dawn effect by coming on prior to channel 2. While certainly not required, most people use True Actinic or Blue Plus bulbs in channel 1 because it creates a nice blue color in the tank prior the more white bulbs coming on for a daylight look.
Bulb locations:
While it is always best to put some thought into the location for each color of bulb in your fixture, the good news is it will make very little difference. The light all tends to blend together upon leaving the fixture mixing individual colors. Generally we recommend putting the bulbs with the fewest quantity towards the middle of the tank. For example, if you only choose 1 Aquablue Special bulb, put that in the middle to make it more even and put your Blue Plus on the edges since you will likely have many of them. The result will be the most even output.
Examples:
Here is an example using an 8 bulb fixture with a nice blue sunrise sunset and a 12-14K output, this will look like the first 5-10 feet deep in the ocean when diving/snorkeling.
Here is an example using a rich blue combination like a deeper dive in the ocean with lots of fluorescent pop in the corals:
For more bulb combination ideas, check out our color temperature guides here.