Building an over-engineered Dutch aquascape
This is the ongoing record of a living, measured Dutch 90P, built around automation, instrumentation and a habit of measuring the things I would otherwise guess. Temperature, pH and conductivity are logged around the clock; PAR is measured by hand. The tank is unfinished. The record is not.
Follow the journeySee the tank now
The Lighting Baseline
The original ADA Solar RGB survey, 8 August 2026. The fixture has since been replaced; this survey is kept as the baseline.
I bought a PAR meter because I thought my six-year-old light was wearing out. About four weeks after planting, the plants near the ends looked less colored up than the ones under the middle of the fixture. That is an impression formed early in a grow-in, on fresh aquasoil, while everything was still adapting, and it is what sent me to buy a meter rather than a conclusion I could defend.
Nineteen underwater readings showed something else. The original Solar RGB still produced strong center output after roughly six years of use, but PPFD distribution across this 90P was highly uneven. Nothing in the tank read below the working range for what was planted there.
Two qualifications belong with that, and the survey states both. Every reading is taken at canopy height rather than at the substrate, which is several inches closer to the light. And the working ranges those readings are compared against are this project’s own targets, because the four most cited sources disagree about what a planted tank needs by up to five times, and the only per-plant table among them was produced with a lighting manufacturer.
That result changed the project from a tank dashboard into a record of decisions that could be checked, and it stopped me buying a light that would not have fixed anything.
Read the complete baseline survey
The light now
On September 17, 2026 a Chihiros WRGB II Pro 90 replaced the Solar RGB: a bar the length of the tank, with four controllable channels and its own schedule, where the pendant was on or off. It runs at R125 G95 B130 W0. Its first full survey covered 15 positions; across the 15 positions both surveys measured, the average rose from 100 to 113 µmol and the highest-to-lowest ratio narrowed from 3.0× to 2.5×. That survey was taken with the fixture lower, the sensor at different depths and an earlier channel mix, so it is not yet a like-for-like comparison, and the Solar RGB is kept until there is one.
Experiment 006 · Solar RGB versus Chihiros · The current survey
24-Hour pH Profile
Every published figure on this site is drawn from the same record. Below is the most recent complete 24-hour cycle: pH sampled at approximately five-minute intervals and averaged hourly, with the photoperiod indicated. Values are read from the database at request time, not transcribed.
The software keeping this record · Why pH drop and not a ppm figure
Current Status
Current · reviewed November 2, 2026
Shaping the Dutch groups, about four months in
The tank is past the sparse grow-in. The work now is shaping distinct Dutch groups, controlling final canopy height, keeping the groups separated, developing the foreground, testing a new Blood Red SG group for color, and holding CO₂, light and fertilization steady. It is not finished: some hair algae remains, and there are localized cyanobacteria-like mats in parts of the foreground.
Working on now
- Shaping distinct groups and controlling final canopy height
- Keeping separation between neighbouring groups as they fill
Next actions
- Repeat the PAR survey under the current channel settings, at the baseline's fixture height and depths where possible
- Measure PAR at the new Blood Red SG group
Installed and running
- Light
- Chihiros WRGB II Pro 90, installed September 17, 2026 · R125 G95 B130 W0 · ramp up from 9am, full 9:30am – 3:30pm, off 4pm (schedule copied from the fixture’s app, checked November 1, 2026). The original ADA Solar RGB is out of service and kept as the baseline.
- CO₂
- Regulator and solenoid into an inline diffuser · a fixed daily window on an Apex outlet, run by the Apex's own program: on two hours before the light, off when it starts to fade. Off below pH 4.70, after a leak and during water changes. Pearling watches it and alerts if it is on when it should be off · not closed-loop on pH; the logged pH drop is used to review and tune the schedule
- Fertilizer
- 2Hr Aquarist APT 3 · 4 mL/day in one dose, dosed automatically by the Red Sea ReefDose 2
- Circulation
- EHEIM Professionel 5e 700 · ADA Super Jet ES-600 · ADA Vuppa II · AI Nero circulation pump, about 25% by day and 40% overnight, reading 40% now
- pH probe
- Apera Instruments 203DJ-C on the Neptune Apex, since September 19, 2026. The Milwaukee MA911B/2 is retired.
- Measured
- Temperature, pH and conductivity logged continuously · PAR measured by hand · water chemistry hand-tested
- Background
- Clear rear glass, no illuminated background; the room wall is visible behind the tank. The DET panel failed in October 2026 and is out of the tank; it is repairable.
- Plants
- 16 active groups; removed groups stay in the record
Latest entry: Four months in
Instrumentation
The aquarium can run without most of what surrounds it. The extra instrumentation exists because it produces a record: temperature, pH, conductivity, outlet states, maintenance, photographs and hand measurements that can be read together instead of remembered separately.