Why this number
This calculator helps you translate tank volume (and current vs target levels where asked) into a practical iron (Fe) dose using common Flourish / Flourish Iron assumptions. It is a dosing aide — not a full Estimative Index spreadsheet.
Planted tanks need balanced macros and micros. Fixing only Fe while CO₂ or light is chaotic rarely greens plants overnight.
How to use it
- Enter accurate water volume (décor reduces usable liters).
- Follow on-screen fields for current/target concentrations when present.
- Dose into high-flow areas; avoid dumping concentrate on sensitive shrimp.
- Retest after a few days — chase trends, not a single reading.
Limits
- Brand bottle instructions still win if they conflict with a generic chart.
- EI/PPS systems use scheduled macros; this page is element-focused.
- Yellow new leaves may be iron-related; old-leaf yellow often nitrogen — see yellow leaves troubleshoot.
Related dose tools
FAQ
Is this a full EI calculator?
Not yet — it focuses on Fe. Use it with a consistent weekly schedule and test kit.
Can I dose every day?
Only if your method calls for it (some lean daily micro routines). Beginners usually do better with fewer, measured doses.
Will more Fe stop algae?
Not by itself. Balance light, CO₂, and cleanup first.
Safe for shrimp?
Dose carefully and avoid copper-heavy products in shrimp tanks. When unsure, half-dose and observe.
What if plants still yellow?
Map old vs new leaves and check CO₂/light before stacking bottles.
Field notes from our tanks
We treat calculator output as a starting hypothesis. After you change light, CO₂, or stocking, give the tank several days and retest before stacking another change. Most algae and melt episodes come from two changes at once, not from a single “wrong” number on day one.
Keep a small notebook (or phone note) with tank dimensions, KH, photoperiod, and the date you changed livestock. That record makes the next calculator run faster and keeps Budget Setup / Troubleshoot links honest for your exact system.