AquaCalc

The planted tank, worked out.

Fifteen free calculators, a tank that remembers your numbers, seventy-five plant profiles and the science behind all of it. No ads, no login, no tracking.

See what’s inside About AquaCalc
15
Free calculators
75
Plant profiles
45
Cited guides
0
Ads or tracking

My Tank

Your numbers, remembered. Log a pH reading — every calculator follows.

Open My Tank → How it works
My Tank · 180 L planted DISSOLVED CO₂ 28.4ppm ▲ in range pH 6.62 KH 4.0 · logged 2h ago NITRATE 18ppm EI dosing · 3×/week NEXT WATER CHANGE Sat 50% · 90 L RO blend CO₂ STABILITY · 14 DAYS My Tank · 180 L DISSOLVED CO₂ 28.4ppm ▲ in range pH 6.62 KH 4.0 CO₂ STABILITY · 14 DAYS

Tools

Fifteen calculators. Volume, CO₂, substrate, filter, fertiliser. Nothing to sign up for.

See all tools
CO₂ CALCULATOR From KH and pH KH (dKH)4.0 pH6.62 DISSOLVED CO₂ 28.4 ppm Target 25–35 ppm for most planted tanks VOLUME 182 L DOSING 6.4 mL RO MIXER 3:1 CO₂ CALCULATOR From KH and pH KH (dKH)4.0 pH6.62 DISSOLVED CO₂ 28.4 ppm Target 25–35 ppm

Plantbase

Seventy-five species, properly profiled.

Browse plants How to prepare
Java fern Leptochilus pteropus Easy Low light No CO₂ needed Rotala H’ra Rotala rotundifolia Medium CO₂ beneficial Foreground Easy Low light Java fern Leptochilus pteropus Easy Low light Rotala H’ra Rotala rotundifolia Medium Foreground Easy Low light

Learn

Forty-five guides, cited and honest.

Read the guides See what’s coming
Cited What “stable CO₂” actually means Cited What “stable CO₂” actually means

One number, all four.

Take one CO₂ reading and watch AquaCalc follow it — from the target, to your tank, over a fortnight, to the science behind why it matters.

  1. Plantbase The target 30ppm what your Rotala wants
  2. Tools Your reading 28.4ppm from your own KH & pH
  3. My Tank Held for 14 days ±1.2ppm barely drifted
  4. Learn Why it matters Steady beats a spiky 30

Everywhere else, the number is where the help ends. Here it’s where it begins.

Just published

What’s new →
Plant profile

Weeping moss

A distinctive aquarium moss whose fronds arch up and then droop as they mature, giving a soft weeping…

View plant → Water chemistry

Calcium:magnesium ratio

The '3:1 calcium to magnesium' rule is everywhere in the hobby. But it is borrowed from a soil theory that…

Read guide →

Coming tomorrow A rule about bottles, mistaken for a rule about tanks — see what’s next →

Free download

Get the planted tank cheat sheet.

Subscribe and we’ll send you our Planted Tank Cheat Sheet — target parameters, the CO₂/pH/KH table and a plant-deficiency quick-guide, on one PDF to keep by your tank. Then a short email whenever we publish a new science-backed guide.

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