AI Hydra 64: Did we just change light testing FOREVER? | BRStv Investigates

In this BRStv Investigates, Randy focuses on the Aqua Illumination Hydra64 LED Light to show off our new approach to testing LEDs and give you a solid foundation for choosing the right LED light for your reef tank.

When setting up a new reef tank light, there are four critical questions that you need to answer before using an LED light successfully. Our series of tests were set up specifically to answer these questions and formulate data-driven recommendations for setting up a Hydra 64 LED Light.

  • How high should I mount the LED fixtures?
  • How many do I need and what is the optimal spacing over my tank?
  • What kind of Spectrum is the light capable of?
  • What settings should I use for my tank type?

You can expect to get a solid understanding of the Hydra64 performance and obtain the necessary knowledge you need to make installation quick and easy over either an LPS/Softie tank or an SPS dominant display. The data also helps to paint a much clearer picture of how LED lights in general are effectively lighting our reef tanks.

Mounting height experiment
Aqua Illumination Hydra 64 PAR Grids

Mounting Height

We mounted a single Hydra 64 at 6 inches from the water’s surface and set it to run at 100% output across all 7 color channels. We took a full grid of PAR measurements and then raised the fixture mounting height in 1 inch increments, recording a new PAR grid at each increment.

What we’re looking for is the best spread possible, meaning a reduced center hotspot and increased PAR on the outer edges while also minimizing the amount of light spilled into the room. Upon comparing the grids and calculating the average PAR values, the sweet spot was obvious.

At 6 inch mounting height, there is an average PAR of 335 with a super intense hotspot in the center of over 1000 PAR. As we progressed, the average PAR values across the entire grid continued to drop but we experienced a much more even spread throughout indicated by the rising outer ring measurements and reduced center hotspot. Once we hit a mounting height of 13”, our average PAR loss across the entire grid surpassed our 15% loss threshold so we called it.

At 12 inches from the water’s surface, you will get the best balance of light spread with minimal light spill over a 24” x 24” area using the Hydra 64 HD LED Light.

Aqua Illumination HMS Mounting System
It just so happens that 12" is about the maximum height of the single and multi-light Aqua Illumination HMS mount kits making this 12” height fairly easy to achieve with the compatible mounting solutions. 

Fixture Spacing

To test spacing multiple lights on a longer tank we mounted two Hydra 64 fixtures over a 48” long 120-gallon tank for LPS dominant systems and then added a 3rd fixture to get some data for SPS dominant systems. Generally speaking, LPS systems will have a lower demand for light compared to SPS dominant tanks and it is important for you to consider these requirements before lighting your tank.

We started taking PAR measurements with the lights evenly spaced from the center of each fixture over the top of the 4ft tank. We then increased the distance between the fixtures, 1” at a time, until we saw the best coverage with the most even spread of PAR across the entire grid.

LPS Coral Spacing Results
SPS Coral Spacing Results



Hydra 64 Fixture Spacing For LPS and Soft Coral Reef Tanks

After reviewing the data it was clear that spreading two fixtures a little farther apart, 14” from the left and right edges yielded the best results with the most evenly distributed PAR for LPS and Soft Corals.

Hydra 64 Fixture Spacing For SPS Coral Dominant Reef Tanks

After adding the 3rd fixture into the mix and rotating to a perpendicular mounting position over the 48” 120-gallon tank, we found that mounting one fixture perfectly centered and the remaining two only 10” from the right and left edges yielded the best results.

Hydra 64 compared to ATI Blue Blus

Spectrum Offering

To explore the spectrum, we used a spectrometer mounted underneath the 60-gallon cube to create spectral graphs. We adjusted the output color using the myAI app and individual LED color channel sliders. The Hydra 64 with all channels at 100% produces a very familiar-looking spectrum with a substantial spike around the 420-500nm range.

When compared to one of the gold standards of reef tank lighting, the ATI Blue Plus T5 bulb, we see that although it doesn’t hit as wide of a band in that 420 to 500 range as the ATI, it does provide a pretty solid representation.

Custom BRS Settings Using myAI

Aqua Illumination does not really provide any settings recommendations for the myAI app, you simply get the option of "Easy Setup" which lays out a suitable photoperiod with all channels set to equal output. From here, it is up to you to adjust the intensity of each setpoint. Using the data we collected and our observations and experience, we proceeded to create our own blend. We came up with different custom settings for both an LPS and SPS dominant reef tanks over both the 60-gallon cube and 120-gallon tank.

In order to find those settings, we put an emphasis on the blue color spectrum for PAR and energy for corals. We then adjusted the white channels to fine-tune the visual appearance and also added some red and green sparingly. We adjusted the intensity to accommodate the average PAR requirements of the corals being kept with 75 - 150 PAR for LPS/Softies and 200-350 PAR for SPS corals.

LPS Settings for a 60 gallon cube using Hydra 64 LED Light

Hydra 64 Settings for LPS Corals

With a single Hydra 64 mounted 12” from the surface over a 60-gallon cube tank we targeted a spectrum range with proven results for coral health coupled with a pleasant visual appearance. We then adjusted the spectrum intensity until we achieved an average PAR throughout the entire tank within 75 - 150 PAR.

SPS Settings for a 60 gallon cube using Hydra 64 LED Light

Hydra 64 Settings for SPS Corals

For SPS corals, the target PAR range is 200 - 350 PAR throughout the tank and so we ramped up the intensity across the board to achieve the output we needed. Again, this is a single Hydra 64 mounted 12” above the water’s surface over the 60-cube. 


 We are confident these data-backed settings will produce great results and you now have the necessary knowledge to hit the ground running with your new Hydra 64. One thing to remember is that your particular aquascape and the exact size and shape of your tank will have an effect on performance. That being said the most foolproof way to get your light dialed optimally for your tank is to verify the settings with a PAR meter.

If you are one of those reef tank enthusiasts that just can’t get enough and would like to dive deeper into the subject of reef aquarium lighting, we highly recommend Episode #11 in the BRS/WWC System video series. Ryan does an amazing job explaining aquarium lighting but also makes a strong case about T5/LED hybrid lighting and why this hybrid technology functions so well over SPS dominant reef tanks.

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