Reef Health Dashboard
Green/yellow/red bands track Randy Holmes-Farley's optimal-parameters consensus. Move toward the middle of the green band over days, not minutes.
How this is calculated
Green / yellow / red bands sit on a consensus of Randy Holmes-Farley's optimal-parameters guide and the Triton "method" reference values:
- Alkalinity: green 7–11 dKH, yellow 6–7 or 11–12, red <6 or >12
- Calcium: green 380–450 ppm, yellow 350–380 or 450–500, red <350 or >500
- Magnesium: green 1,250–1,400 ppm, yellow 1,150–1,250 or 1,400–1,500, red <1,150 or >1,500
- Salinity: green 34–36 ppt, yellow 33–34 or 36–37, red <33 or >37
- pH: green 7.9–8.4, yellow 7.7–7.9 or 8.4–8.6, red <7.7 or >8.6
- Nitrate: green 2–10 ppm, yellow 0.5–2 or 10–25, red <0.5 or >25
- Phosphate: green 0.02–0.10 ppm, yellow 0.005–0.02 or 0.10–0.25, red <0.005 or >0.25
- Temperature: green 76–81 °F, yellow 74–76 or 81–83, red <74 or >83
These are conservative bands for mixed reefs. SPS-dominated tanks tighten further (alk 7.5–9, NO₃ 1–5, PO₄ 0.02–0.05). Soft-coral / LPS systems are forgiving — they don't crash at 12 dKH or 0.25 PO₄, but they don't thrive either.
FAQ
- Is 'green = perfect'?
- Green means within the safe range and unlikely to cause acute problems. Coral health depends on stability inside that band, not on hitting a specific midpoint. A tank that holds 8.0 dKH ±0.2 for a year is healthier than one that bounces between 7 and 10 dKH every week.
- What if everything is red?
- Fix salinity and temperature first — those are environmental, not chemical, and livestock survive everything else better when those two are stable. Then work alkalinity in 1 dKH/day steps, then calcium, then magnesium. Address nitrate/phosphate last, slowly, over weeks — fast nutrient drops crash bacteria and trigger dinoflagellate blooms.
- Why is nitrate green at 2–10 ppm, not zero?
- Zero-nutrient tanks starve corals (especially LPS and softies). The 'ultra-low-nutrient' fashion of 2010-era SPS care drove a lot of tank crashes from dinoflagellate outbreaks once natural sinks (food, fish poo) couldn't keep nitrate measurable. Aim for measurable but low.
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<iframe
src="https://reefcalcs.com/embed/reef-health-dashboard/"
width="100%"
height="720"
style="border: 2px solid #111412; max-width: 720px;"
loading="lazy"
title="reefcalcs Reef Health Dashboard"
></iframe>Sources & references
- 1.Randy Holmes-Farley — Optimal Parameters for a Coral Reef Aquarium (Reef2Reef thread)https://www.reef2reef.com/threads/optimal-parameters-for-a-coral-reef-aquarium-by-randy-holmes-farley.173563/
- 2.Triton — Method reference valueshttps://www.triton.de/en/
- 3.Randy Holmes-Farley — Magnesium in Reef Aquariahttps://reefs.com/magazine/aquarium-chemistry-magnesium-in-reef-aquaria/
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