Experiment 006

Original ADA Solar RGB versus Chihiros WRGB II Pro 90

The fixture that was actually installed. The Solar RGB survey of 8 August is the baseline and the Chihiros readings are the replacement dataset. The two surveys so far were not taken under matched conditions, so this is not finished.

◐ In progress

Question

Does the Chihiros WRGB II Pro 90 give this 90P a more even PPFD field than the original Solar RGB, at the plant positions that matter?

Background

The Solar RGB survey found strong centre output and a wide spread between positions, the highest reading being more than three times the lowest. The constraint was coverage, and raising the pendant made the ends worse (Experiment 002). A bar the length of the tank starts from a different geometry, and it has four channels where the pendant had none. On 17 September 2026 the Chihiros replaced the Solar RGB; the Solar RGB is kept as the reference.

Hypothesis

A full-length bar would narrow the spread between the highest and lowest positions. Stated before a matched comparison exists, so it can be shown to be wrong.

Recorded before measuring, so it can be shown to have been wrong.

Equipment

ADA Solar RGBChihiros WRGB II Pro 90Apogee MQ-510

Method

Same tank, same Apogee MQ-510, same numbered positions. The baseline is the Solar RGB survey of 8 August 2026 (fixture 12″ above the water, sensor depth recorded per position). The replacement dataset so far is the Chihiros survey of 18 September 2026 (fixture 7.25″, sensor at 6 or 10″, channels R86 G86 B95 W15), plus spot checks since. A finished comparison needs a Chihiros survey with fixture height and sensor depth matched to the baseline, at a recorded channel setting.

Measurements

  • Baseline: 8 August 2026, ADA Solar RGB, nineteen positions, depth and fixture height on every reading
  • Replacement: 18 September 2026, Chihiros WRGB II Pro 90 at R86 G86 B95 W15, fifteen positions, depth and fixture height on every reading
  • Spot checks under the Chihiros at R115 G85 B120 W0, 10 October 2026, three positions
  • Planned: a full Chihiros survey at the baseline's fixture height and sensor depths, at the current channel setting

Observations

  • Across the fifteen positions measured in both surveys, the Chihiros survey reads higher on average and the spread between highest and lowest is narrower. The figures are computed from the stored readings on the experiment and tank pages.
  • The two surveys differ in fixture height, sensor depth, spectrum and plant height, so the difference cannot be attributed to the fixture alone.
  • The Chihiros survey was taken the afternoon before a replant that moved several groups, so its positions describe the layout that morning.

Future work

  • Survey every live position under the Chihiros at the baseline's fixture height and sensor depths, at a recorded channel setting.
  • Record the channel setting against every reading; on this fixture it is a variable, where on the Solar RGB there was none.
  • Derive DLI for both from PPFD and photoperiod.
  • Publish the comparison whichever way it comes out.

Related documentation

PAR Measurement MethodologyHow PAR is measured on this tank, and what the numbers do and do not mean.→Lighting ExperimentsMounting height, fixture position and the comparison between the original Solar RGB and the Chihiros that replaced it.→Measuring PAR Distribution Across a 90P Using the Original ADA Solar RGBNineteen underwater readings across a 90 cm tank under one ADA Solar RGB. The full method, the raw data, and what the distribution shows.→

Results describe this specific aquarium under the conditions recorded above. They are observations, not universal recommendations.