Aquarium CalcDosing
Fertilizer or treatment “5 ml per 50 l” recalculated for your real volume, for a whole course, with how long the bottle lasts.
Aquarium calculator for Android
Know your real volume.
A 120 × 40 × 50 cm tank is not 240 litres. Glass, substrate and the gap to the rim take their share — and every dose you pour depends on what is left.
- Free
- Works offline
- Several tanks
Water volume197 L
Where the litres go
240 litres on paper, 197 in the water.
The app subtracts what is not water and shows the number you should actually dose by.
| Full volume by the glass | 240 L |
| Glass walls and bottom | −7 L |
| Gap to the rim | −19 L |
| Substrate (a third of it is still water) | −17 L |
| Rocks and wood | −4 L |
| Real water volume | 197 L |
Rectangular, cube, cylinder, bow-front and corner tanks. Centimetres or inches, litres, US or UK gallons.
Four tools
The numbers you look up every week.
Water change
How many litres to change to bring nitrate from 40 to 20 — and how much to change weekly to keep it there.
Salinity
Sea salt for a fresh batch of water, or how to raise and lower salinity in the tank. ppt or density.
AI helper
Cloudy water, algae, a new tank that will not cycle, fish that should not share a tank — ask in your own language.
AI helper
Ask about your tank.
The helper knows your tank's size and water volume, so the answer is for your aquarium and not a forum quote.
- Water problemsCloudy or green water, ammonia and nitrite spikes, a tank that will not cycle.
- Fish and plantsWho can live with whom, how many fish fit, why the plants are melting.
- 3 free questions a weekPlus one more for every short video you watch, up to three a week. With the subscription: up to 100 questions a day and no ads.
Inside the app
Every tank on one screen.
Details
The small print.
| Several tanks | Save every tank once — name, shape, sizes — and all the tools use its real water volume. |
|---|---|
| Units | Litres, US or UK gallons, centimetres or inches. Picked from your region, switch any time. |
| Safety | The app gives numbers, not prescriptions. Doses follow the label on your bottle; large water changes are flagged as a big swing for the fish. |
| Languages | English, Українська, Español, Português, Deutsch, Français, Italiano, Nederlands, Polski, Čeština, Română, Български, Eesti, Русский, Türkçe, Bahasa Indonesia, Tiếng Việt, ไทย, हिन्दी, العربية, 日本語, 한국어. |
| Price | Free with ads. An optional monthly subscription removes all ads and unlocks up to 100 AI questions a day. |