Frequently Asked Questions

Browse below for answers to commonly asked questions.




+ Should I perform regular maintenance on my light?

Yes, we recommend using compressed air to clean out the light every 1-2 months to prevent the buildup of dust and debris. Wiping down the light with a dry cloth regularly will also help prevent salt creep buildup.

+ Does deep-cleaning my light void the warranty?

Opening up your light to deep clean will void the warranty and should not be necessary if regular maintenance is performed. If you have verified with Kessil that your light is outside of warranty and are experiencing issues with the light overheating, please contact Kessil for deep cleaning instructions.

+ How long is my light under warranty?

All Kessil lights come with a one year warranty. US customers can register their product for an additional one year of warranty here. Warranty is non-transferable and only applies to the original owner of the light.

+ How do I know if my light is under warranty?

Please contact Kessil with the serial number to the light and we can notify you if your light is still under warranty.

+ Where can I get a replacement part?

Please contact Kessil customer service at for replacement part inquiries.

+ If my light is broken, can I send it in for repair?

Yes, we do offer repair services within the US. If you have a repair service inquiry, please email us at for more information.

+ What is the lifespan of my light?

Our lights have a normal life expectancy of 35,000 hours, about 5-7 years for most customers. There are many factors that can reduce the life expectancy of the light such as the environment (humidity, moisture, salt creep, and temperature) as well as the maintenance of the light. Regular cleaning and maintenance of the light are important and if not performed, it may affect the longevity of the light.

+ What are the PAR measurements of your lights?

We do not have any published PAR reading online. We here at Kessil do not use PAR for measurement or comparison for the following reasons:

  • PAR does not accurately capture all the wavelengths needed for livestock growth and coloration. PAR meters cannot distinguish the effects of different wavelengths as higher PAR values do not necessarily translate to be more efficient. Eg. 50 PAR of green vs 50 PAR of blue. Theoretically, blue light is far more valuable, as green light does not contribute to coral or plant growth. In addition, PAR meters can have less sensitivity in the blue/UV range which includes the key spectrums for coral growth.

  • PAR does not value wavelength combinations. Kessil has spent years fine-tuning the spectrum to perfect wavelength combinations. Kessil’s initial theories were based on established successful practices and the most current biological research, all of which were verified independently through years of testing and experience. Kessil has refined lighting formulas that have proven to be effective and efficient.

+ Why does my tank shimmer?

Kessil lights are famous for their superior shimmer throughout the aquarium hobby. Shimmer occurs when a point source light interacts with the surface agitation of the water, replicating the natural look of sunlight on the ocean floor. This is made possible by the light’s powerful Dense Matrix Array.

+ What is a Dense Matrix array?

Typical LED’s have each LED Chip under their own individual lens, LED’s are then spaced apart resulting in a light source with poor dispersion, inconsistent color spectrum, and poor color mixing. Kessil’s unique Dense Matrix Array features multiple LED Chips in close proximity under a single lens. This technology allows for lights with a smaller form factor and superior optics while eliminating the drawbacks of traditional LED’s. Learn more about the Dense Matrix Array here.

+ Is it normal to notice a variance in color between my Kessil Lights?

The slight variances you are seeing in our color spectrum can sometimes happen. This is simply due to the way we craft our LED array and chips. Based off of our ‘Kessil logic’, we can say for fact that the color variances will not affect your coral growth.

+ What is Kessil Logic?

Kessil Logic locks in the ideal spectrum for coral and plant growth, meaning your tank will thrive regardless of the colors you choose.

+ Can I put my lights on a timer?

Yes, you can put your lights on a timer but we recommend using our Spectral controller, Spectral controller X, or the WiFi dongle to be able to use the light to its full ability.

+ Where can I buy Kessil lights?

You can buy kessil lights at your local fish store or at online retailers such as and Bulk Reef Supply




+ Should I connect directly to the AP9X/WiFi Dongle or should I use my home WiFi?

We recommend connecting directly to the AP9X or WiFi Dongle as it provides a more stable / reliable connection. The difference between the two connection options is that one requires you to join the Kessil network (the AP9X/WiFi Dongle) before making any changes whereas the other method doesn’t require you to change networks at all.

+ Should I connect multiple AP9X’s together wirelessly or with K-link cables?

If you connect multiple AP9X’s with K-link cables it will be an easier setup process and provide a more stable connection. You’ll need to turn off the Wi-Fi (Hold the Wi-Fi button for 3 seconds) on every light except the master unit which will connect to the app.

+ Help! My light did not appear in the dashboard (or it gave me a disconnection error). What should I do?

As long as you are connected to the proper WiFi network; head over to the dashboard, press the “+” icon in the bottom right corner, select “Quick Reload”, press “Quick Reload” again, then you'll see a single select option screen that should list your light / dongle. Select your unit and wait for the loading screen to finish. You should now be back at the dashboard and see your light. If this did not work, give us a call at (510) 620-5250.

+ How should I clean the reflectors on my AP9X?
  • Unplug the fixture from the external power supply - ensure the LED arrays have cooled off before cleaning.

  • Apply RODI water or Rubbing alcohol directly to the LED array and reflectors, allow it to sit for one minute to soften any salt crystals that have accumulated.

  • Lightly wipe away any debris with a microfiber cloth. Be sure to dry the arrays with a separate microfiber cloth or paper towel.

  • Check for any spots you may have missed. If there is no longer any debris and the arrays are dry you can then mount your light back on the tank.

+ Can I use the reflector accessories with my AP9X?

No. Our AP9X has built in 60-degree reflectors which eliminates the need to use our other reflector accessories. These reflectors are oval shaped to improve the rectangular spread this light offers.




+ How high can I mount the A500X without a reflector?

Assuming you have a standard 24” tall tank we recommend mounting the A500X 6- 10” above the water.

+ What is the recommended mounting height for the A500X?

The mounting height changes based on the reflector. Assuming a standard 24” tall tank, we recommend the following mounting heights.

  • No reflector - 6-10” from the surface of the water

  • 55 Degree Reflector - 12-24”

  • 35 Degree Reflector - 24-36”

*Please note that some coral species require different light intensities. These are a guideline for a standard mixed reef with some SPS tanks.*

+ What is the recommended depth penetration for the A500X?

The depth penetration changes based on the reflector. Assuming a mounting height of about 8” off the water, the following tank depths can be used.

  • No Reflector - 24” deep

  • 55 Degree Reflector - 36”

  • 35 Degree Reflector - 48”

*Please note that some coral species require different light intensities. These are a guideline for a standard mixed reef with some SPS tanks.*

+ Is the power supply the same for the AP9X? They look similar.

Yes! The A500X uses the same PSU that our AP9X (and older AP700 model) uses.




+ How do I reset my AP700?

Please perform a full reset and only use one device to control and connect the light. We recommend the phone app. Also, make sure that you thoroughly follow the reset instructions without bypassing any steps.

Reset Instructions:

  • Open the phone app. Go the Main Page --> "Menu" --> "*Reset App Data"

    *This will delete all data from your app including programmed schedules

  • Reset WiFi on AP700 fixture by pressing the color "down" and intensity"+" buttons simultaneously. Make sure the blue WiFi indicator is flashing.

  • Unplug AP700 from the wall outlet for 5 minutes

  • Plug your AP700 back into the wall outlet making sure the power indicator is red and turn on WiFi on the AP700 by pressing the "down" and "+" buttons simultaneously. Make sure the blue WiFi indicator is flashing.

  • Go to phone Settings -> WiFi, look for the Kessil SSID and forget the network. For iPhones press "information" and "Forget this network". For Android phones, press the network for 2 seconds and click "Forget Network".

  • Open the app to start the connection process.




+ Do Red/Amber and RGV chips in the A360X boost plant and coral growth?

No, the addition of Red/Amber or Red/Green/Violet does not include photosynthetically relevant light and is used to highlight colors in your tank and make your livestock pop!

+ Are Acclimation mode, Lunar modes, and effects available for A360X Tuna Sun using the Wifi Dongle or Spectral X Controller?

No, currently these features are not available to the A360X Tuna Sun but will be added with future firmware updates.

+ What does the Narrow Reflector attachment do?

The Narrow Reflector is a magnetic attachment for the A360X meant to narrow the spread and triple the light intensity. By adding this attachment you can increase the depth penetration of your light to 2.5’ to 5’. This attachment is great for spotlighting coral or deep tanks.

+ What’s the difference between the A360WE and the A360X?

The A360X is the upgraded version of the A360WE. Not only is the A360X 30% smaller than its predecessor, but it also has a 50% greater coverage. The A360x boasts a redesigned vortex fan that prevents the buildup of dust and debris inside the light, reducing the need for cleaning. The A360X now features red, green, and violet chips in the Tuna Blue model and red and amber chips in the Tuna Sun model to highlight all the colors in your tank. The A360X is also compatible with the WiFi dongle allowing control via a smartphone app.


WiFi Dongle / Spectral Controller


+ What lights are compatible with the WiFi Dongle?

A360X and A500X are both compatible with the Wifi Dongle using the K-Link connection.

+ Do I need a WiFi Dongle for every light?

No but you can use one dongle per light if you prefer a sleek look. A single dongle can control up to 32 lights when the lights are daisy-chained with our K-Link Cables.

+ Is the WiFi Dongle APEX compatible?

Yes, the WiFi Dongle and AP9X are now APEX compatible.

+ How do I reset my WiFi Dongle?
  • Go to the setting in the app and select ‘reset the app’ (if the app will allow you to this point- if not uninstall the app and redownload it)

  • Use a small object to hold down the button on the dongle for 10 seconds until there is a flashing red light, this is a full reset of the dongle.

  • Go to your phone's WiFi settings and forget the WiFi dongle's network

  • Unplug the dongle for a few seconds and then plug it back in (be sure to push the dongle all the way in, it will usually make a clicking sound)

  • Go to the app and start the connection process again for the dongle.

*If using iPhone and the WiFI Dongle will not let you get past scanning the QR Code, try the following. After you unplug the dongle (Step 4) delete the app and restart your phone. Once your phone is back on redownload the app and try again from step 5.

+ Is the WiFi Dongle compatible with 5Ghz networks?

No, the WiFi Dongle is currently not compatible with 5GHz networks. Please us 2.4GHz networks when connecting to the WiFi Dongle

+ What is the difference between a direct connection and connecting with the router?

Connecting your WiFI Dongle through your router allows for better stability and control range while allowing you to maintain an internet connection on other apps while controlling your lights. By connecting directly you must go into the WiFi Dongle’s network every time you want to control the lights. Setup is similar with either option.

+ How can I backup my settings and schedules on the Wifi Dongle?

Logging into your social media account on the WiFi dongle app allows your personalized settings to be saved to the cloud.

+ What is the best schedule for my tank?

Each tank is unique and has different lighting requirements. Kessil Logic ensures that no matter what color you choose your plants/corals are getting the key spectrums needed for photosynthesis. Intensity and duration will be individual to your tank. If changes to intensity and duration are made, be sure to make changes slowly to give your livestock time to adjust.

+ Can the Spectral Controller X be used with older models of lights?

Yes, the Spectral Controller X has a K-Link port for the A360X as well as a 0-10V port that is compatible with all older models. If using the Spectral X controller without an A360X it must be powered using a Micro USB to USB cable and a USB Power Adapter.


Firmware Updates


+ How do I update the firmware on my AP700 or spectral controller?

Plug the AP700 or Spectral Controller X into a windows computer using the firmware cable that came with the unit. Download the latest firmware update from our website and follow the directions. Contact us at if you have any issues downloading the update.

+ Can I use a Mac to update my firmware?

Firmware updates can only be performed using a Windows computer.




+ Can Mounting Arms be used with euro braced tanks?

Mounting arms can be used with eurobraced tanks if used with the Extension Mount. The Extension Mount can be screwed into the stand or into the wall.

+ Can the A-Series Gooseneck be used in euro braced tanks?

Yes, goosenecks can be used with euro braced tanks. Rotate the gooseneck base so that the clamp lies horizontally, with the side with 3 holes facing up.




+ My light won’t turn on- what do I do?

Before you contact Kessil for help with your light, try some of these troubleshooting steps to see if this resolves the issue:

  • The light may have overheated which is caused by dust and debris that may be inside. Please thoroughly blow out the vented areas with compressed air for a few sessions.

  • Disconnect the light from any surge protector, controllers, cables, or timers to verify the light is functioning/non-functioning.

  • Unplug the power supply plug completely from the wall outlet for around 15 minutes, and plug it back to see if it works.

  • If another light is available, please try to swap the power supplies to check if the power supply is the cause.

  • You can also view a segment on our YouTube Channel for more information on how to maintain your light. Click on the 17:16 time stamp to view the Basic Maintenance instructions.

+ My Fan is making a loud noise is this normal?

Usually, this may be due to overheating caused by dust inside the light and/or debris lodged inside the light. Please try to use canister air several times more to blow air thoroughly through the vents on the light to remove dust or debris. Please unplug the unit, turn it so that the glass lens is facing sideways, and gently shake it to try to remove any debris. Please note whether the sounds change at all after performing these steps.