AI Hydra LED Lighting: PAR Ranges, Mounting and Scheduling for Reef Tanks

Reef lighting arguments usually boil down to one question: can the fixture push enough PAR to the substrate for SPS without cooking the softies up top? The AI Hydra 32 HD Black is built around solving exactly that problem, and it does it with a spread of individually addressable diode colours rather than one blunt white LED array.

PAR output from surface to substrate

Mounted around 20 to 25cm above the water line on a standard 4 to 6 foot reef tank, a single Hydra 32 HD can deliver PAR readings in the 400 to 600 range at the surface, dropping to somewhere between 150 and 300 at 30 to 45cm depth depending on intensity settings, water clarity and how much of the spectrum is dialled toward blue versus white. That range matters because SPS corals like Acropora and Montipora generally want 250 to 450 PAR to hold colour and grow densely, so they do best placed on the upper rockwork or shallow sandbed in a tank running one Hydra per 60 to 90cm of length. LPS corals such as Euphyllia, Trachyphyllia and most mushroom corals prefer considerably less, often 80 to 150 PAR, so they sit lower on the rockwork or in the sand where the light has had more chance to attenuate through water column and glass.

Running two Hydra 32 HD units side by side over a wider tank evens out the PAR curve so you don't get a hot spot directly under each fixture and a dim trough between them. For anyone stacking multiple units and wanting them to fire off one schedule, a controller such as those in our controller range can sync everything and log real par-relevant parameters alongside the lighting program.

Mounting over a typical Brisbane tank

Most Brisbane reef setups run open-top rimless tanks on cabinet stands, and the mounting choice changes what the fixture can actually do. The AI HMS Single Arm Mounting Kit clamps to the back rim or a horizontal bar and lets the Hydra swing out over the tank without a hanging kit taking up ceiling space, which suits units where you want to tilt the light forward for viewing angle or pull it back for maintenance access. The AI Prime Hanging Kit Black is designed more for the smaller Prime series fixtures and uses cable suspension from above, which keeps the water surface completely clear for skimming, feeding or netting fish without knocking into an arm. Neither kit changes the light output itself, but the height and angle they allow will shift your effective PAR at any given coral by a noticeable margin, so it is worth measuring with a PAR meter after installation rather than assuming factory settings will match another tank's numbers.

Spectrum scheduling through the app

The real advantage of the Hydra system over a fixed-spectrum light is the myAI app, which lets you build a full 24 hour cycle with separate intensity curves for each diode colour. A typical program ramps up violet and blue channels first thing, layers in white and green through a midday peak, then tapers back to blues and reds for a sunset effect before the tank goes dark. You can save these as templates, clone them across multiple Hydra units, and adjust individual channels without touching the whole curve if one coral is bleaching or a particular colour is washing out under camera lights. It is a genuinely useful tool for slowly acclimating new SPS frags to higher intensity over a few weeks rather than shocking them with full output on day one.

Getting the setup right

Start any new Hydra install at 40 to 50 percent total intensity and increase gradually over two to three weeks while watching coral colour and polyp extension. Pair a PAR meter reading with actual coral response rather than relying purely on the app's percentage figures, since tank depth, glass thickness and water clarity all change the number that reaches the rock.

Because AI fixtures, mounting kits and matching controllers move in and out of our lineup as demand and freight shift, the easiest way to see current models and accessories is to check out our stock list for AI and other reef lighting, where we keep the range updated as it changes.