What type of tank is Kessil's AP9X good for?

The AP9X best matches rectangular-shaped aquariums. Maximum coverage advertised by Kessil is 24" x 48" for a single fixture which creates PAR zones suitable for Soft corals, LPS, and mixed reef tanks with SPS in the upper part of the water column. Kessil specifically designed the optics to provide an oval or oblong-shaped spread of light which is why you can cover such a large area and still get suitable PAR for a mixed reef. 

How high should I mount the Kessil AP9X from the water's surface?

The BRS Recommended mounting height was tested to be 10" from the water's surface over a 24" x 24" area but that does create a hotspot toward the middle of the tank. If you're using the light over a tank measuring 36" - 48" long, you can raise the light up as high as 15" from the water's surface to get the spread and reduce the severity of the concentration of higher PAR toward the middle.

Recommended Mounting Height: 10" - 15" from the water's surface.

What is Kessil Logic?

Kessil Logic is the proprietary technology Kessil employs on all of their reef aquarium lights that allows the user to adjust the appearance of the light but not alter the core output spectrum that is optimized for photosynthesis among the coral.  This means you can adjust the light to match your particular preference in terms of appearance without the worry of falling outside a spectrum that is suitable for coral growth. 

With the AP9X specifically, you get red, green, and UV supplemental color channels along with the primary white and blue color channels. No matter how you set these channels, the light will maintain a safe spectrum for your corals. This simple approach to tuning is very much a part of what makes Kessil an attractive choice for reef tank owners. When you consider the incredible natural shimmering effect Kessil LEDs create, they really have achieved a unique and impressive LED light that is still unmatched.  

How do I program the Kessil AP9X?

The AP9X comes standard with built-in Wifi and is controlled using the Kessil Wifi app that is available for both iOS and Android devices. 

Connecting to your AP9X

  1. Mount and plug in your AP9X LED light.
  2. Download the Kessil Wifi app.
  3. Create an account and log in.
  4. The app provides step-by-instructions for connecting your device.
  5. Once connected to the light, you can now program your schedule.

Creating a GROUP

  1. From the home screen in the app, click on GROUP at the bottom of the page.
  2. You can create a new group or rename the existing default group. This group name should be unique to your aquarium and is used to group multiple AP9X LED lights together.
  3. Click the BACK ARROW in the upper left, click SAVE.
  4. Drag through the available groups on the home screen to find your AP9X under the default group.
  5. Tap, hold and drag your AP9X fixture into your Custom group or just use the default group. 


  1. With your group selected, click MODE at the bottom of the screen.
  2. Swipe up to access Kessil's Preset schedule or choose "ADD PROGRAM" to create your own.
  3. When creating a program, you have the option of using a template or starting from scratch. The template makes things a lot easier.
  4. After clicking on the TEMPLATE, you can adjust the various setpoints throughout the day. Adjust both output spectrum and time of day for each setpoint as desired.
  5. Click the BACK ARROW in the upper left, click SAVE.
  6. Your AP9X should now follow the saved schedule. 

Should I do regular maintenance?

As with any piece of aquarium gear, it needs a little TLC to provide long-lasting performance. With a light fixture like this, you just need to remove dust and salt creep and clean the optics every 3-6 months. A mildly damp cloth and some pressurized air will make dusting a breeze.