The single pendant fixture over the aquarium, and the subject of most of the measurement work on this site. It supplies all the light the plants receive.
Why I chose it
Chosen for its color rendition, reliability, and long-standing reputation in high-end planted aquascaping. It was bought from Aqua Forest Aquarium as the centerpiece fixture for a pendant-mounted layout.
What I've learned
·Reliable across approximately six years of daily use with no failures.
·Produces a concentrated center hotspot rather than an even field. Measured PPFD at the outer positions is a fraction of the center reading.
·The fixture is narrower than the tank is long, so coverage appears to be the limiting factor on a 90P rather than peak output. Raising it would widen the footprint, but this fixture has no output to spare for the height that would take.
·Raising the fixture appeared to reduce measured light at the ends instead of spreading it (Experiment 002). Those comparison readings were not preserved as a standalone survey, so the test is queued to be repeated.
·The ADA Shade has been fitted throughout. ADA states it prevents light leakage and “enhances downright-illuminance up to approx. 15%”. That is a manufacturer figure for illuminance, which is not PPFD, and it has never been tested here — the shade was on for every reading, so whatever it contributes is already inside the published numbers rather than something to add to them.
·Small changes in front-to-back centring shift the measured distribution noticeably.
Installation
Suspended over the center of the tank at 12 inches above the water surface, with the ADA Shade fitted. It was later found to be mounted slightly off-center front-to-back, which the PAR survey exposed.
Configuration
·Mounted 12″ (about 30 cm) above the water surface, the distance ADA quotes its illuminance figures at
·ADA Shade fitted, and fitted for every PAR reading published on this site
·Operated at 100% output
·Photoperiod 9:30am – 4:30pm
·Switched by the controller as a scheduled outlet
Maintenance
·Wipe the lens when condensation or salt creep appears.
·Check the suspension and cable seating when the fixture is moved.
Known limitations
·The emitter array is narrower than a 90 cm tank is long, so measured intensity falls off sharply toward the ends.
·Raising it to widen coverage appeared to reduce measured PAR at the ends rather than improving it.
·No published PAR distribution data is available from the manufacturer to compare against.
Controller integration
Switched as a scheduled controller outlet (LGT), so the photoperiod is held by the controller rather than by a timer on the fixture.
Current observations
·Running at full output on a 9:30am–4:30pm photoperiod.
·Standing PAR survey in place across twenty positions; center reads materially higher than the ends.
What this item is doing now, as distinct from what has been learned over time.
Maintenance history
No service dates recorded yet. Scheduled replacement applies to consumables; this item is tracked by condition instead.
Six years of trouble-free operation and color rendition that has never been the thing to fix. On a 90 cm tank coverage is the binding constraint, and this fixture does not have the output headroom to buy spread by hanging it higher. The honest answer depends on whether a brighter fixture mounted higher, a wider one, or two smaller ones covers this layout better. That is what the planned comparison is for.
Future upgrade considerations
·A like-for-like comparison against the ADA Solar RGB II is planned (Experiment 004).
·Multiple modest fixtures remain an alternative worth measuring against one pendant.