Does the fish fit your stocking? Are your water parameters right? Is the tank already cycled? Aqualizer calculates, warns and reminds – right in your browser, no app download.
Free forever · No credit card · No download
Seven calculators, ready to use instantly, no account required.
Bubbles per second → mg/L – matched to your stocking.
Calculate now →The perfect mix of RO and tap water for GH & KH.
Calculate now →Net liters, water change volume & substrate deduction at a glance.
Calculate now →Footprint method instead of 1 cm/L – modern stocking without guesswork.
Plan now →Calculate liters from a percentage or straight from your nitrate target.
Calculate now →How many watts does your tank need? A guideline from volume and temperature difference.
Calculate now →Liters, gallons, °C/°F, °dH/ppm – every aquarium unit in one place.
Convert now →Completely redesigned – more overview, more control, more AI.
Real voices from the community.
„I've spent some time with the tool and find it really helpful!“
„I've been using it since setting up my tank, it's helped me a lot.“
„I'm presenting a digital tool for the aquarium hobby. I go into detail on the features and test with you how well it works.“
Einfach Gerken tested Aqualizer and walked through all the features – independent & honest. (German-language review.)
Aqualizer is free forever – one tank, water parameters, cycling assistant and all calculators. No credit card, no expiry date.
If you maintain several tanks or want deeper analysis, you can later switch to Premium in the app – from €6.99 a month, cancel anytime. But you don't have to.
Ready in two minutes – and you'll immediately see what your stocking needs.
Add your tank for freeFree forever · No credit card · No download
Short and clear answers.
Everything about your aquarium in one place: plan stocking and check compatibility, record water parameters and have them analyzed by AI, get reminded of water changes and fertilizing, get guided through a new tank's cycling phase – and share your tank with the community. In short: less guesswork, healthier animals.
The Stocking Advisor is your digital companion, even at the aquarium store counter. Before you buy a new species, check right there: Does it get along with my stocking? Does it have enough tankmates of its own kind? Does it fit my tank? At home you see all your animals at a glance, get warnings for shoals that are too small, and can build a wishlist for future purchases.
It suggests hardscape placement, planting and matching stocking for your tank – as a schematic top-down view with a legend, not a generated image. You can either reposition your existing plants, or plan completely from scratch, even with no idea where to start. Editorially reviewed standard combinations are free to use.
Yes – forever, not a trial. No credit card, no hidden costs. One tank with stocking and water parameters, the cycling assistant, all calculators, and 5 AI credits per month are free forever. You also get 14 days of Premium as a welcome gift. When that runs out, you automatically switch to the free version – nothing is charged and there's nothing to cancel.
No. Premium features are labeled as such in the app, nothing more. You can use Aqualizer for years for free, without anyone reminding you. If you eventually maintain several tanks or want more detailed analysis, Premium costs €6.99 a month and can be canceled monthly.
No – no download required. Aqualizer runs entirely in the browser on your phone, tablet or PC. You can save it as a web app on your home screen – including push notifications like a native app.
For everyone – from beginners with their first tank to experienced hobbyists running several setups. Beginners benefit from the guided cycling assistant and clear AI recommendations. Advanced hobbyists use water parameter charts, treatment plans and the Stocking Advisor daily.
