- Everything here is free and provided as information, not as fishkeeping, veterinary or structural advice.
- We work hard to be accurate — and you should still follow the label on the bottle.
- Dose the water you actually have, not the number on the tank. Every tool on this site exists to tell you the difference.
- Your tank and its animals are your responsibility. We can't see them, test them, or know what's in there.
Who these terms are with
AquariumToolbox (aquariumtoolbox.com) is operated by the person named in our privacy policy. In these terms, "we" and "us" mean that operator. By using the site, you're agreeing to what follows.
What this site is
A set of free calculators and guides for keeping freshwater, planted and reef aquariums. There's nothing to buy from us, no account to create, and no subscription. You can use the tools for your own tanks, or for tanks you maintain professionally, at no charge.
What we promise about the math — and what we don't
We take the numbers seriously, because they're the entire point of the site. Every result is derived from published chemistry and physics rather than copied from someone else's table — molar masses for the dosing tools, the UNESCO equation of state for salinity, the standard mass-transfer relations for evaporation, and named hobby references where the hobby is the source. All the calculators share one calculation engine, so two pages can't disagree about the same water. That engine is covered by an automated test suite checked against reference values, and every result has a "show the math" panel so you can follow the arithmetic yourself.
What we can't do is see your tank. A calculator only knows what you type into it, and the most common source of a wrong dose isn't our arithmetic — it's a volume taken from the label instead of measured, a test kit past its date or read in bad light, or a product whose strength differs from the one we assumed. So we provide the math without a warranty that a given result is correct for your specific tank, and you remain responsible for sanity-checking a dose before it goes into water with animals in it. If a result looks wrong, it might be — please tell us, and we'll fix it or explain it.
- The product label wins. If a manufacturer's instructions differ from anything here, follow the manufacturer.
- Dose against your true water volume, never the size printed on the tank. Glass, substrate, rock and the gap below the rim routinely put a "75 gallon" 15–20% below its name, and a medication dosed to the label is that much of an overdose.
- Medications are the dangerous ones. Copper is fatal to shrimp, snails and other invertebrates at doses fish tolerate, and the gap between a therapeutic and a harmful level is small. Treat in a quarantine tank where you can.
- Change parameters slowly. Corals and invertebrates react to the rate of change more than the value — alkalinity, salinity and temperature swings kill things that a steady "wrong" number wouldn't.
- Never mix concentrated additives together or dose them into the same spot at the same time. Calcium and alkalinity supplements meeting undiluted precipitate out and can cloud a tank in minutes.
- Test before and after you dose. Dosing to fix a number you haven't measured is guessing with livestock.
- Water and mains electricity. Heaters, pumps and lights near a tank should be plugged into an RCD/GFCI-protected outlet with a drip loop, and unplugged before your hands go in.
- Never release aquarium fish, plants, snails or water into the wild, or down a storm drain. It's how invasive species start, and in many places it's illegal.
This isn't professional advice
The site is general information, not tailored advice for your tank, and using it doesn't create a professional relationship between us. For a sick animal, consult an aquatic veterinarian or someone qualified in fish health — a calculator can size a dose, but it can't diagnose. For electrical work, plumbing, or whether a floor or a piece of furniture can carry a filled tank, consult a qualified professional: our weight calculator gives you a number to hand them, not a structural verdict.
What stays your responsibility
- Measuring your tank's real water volume, since every dose scales from it.
- Testing with a kit in good condition, and retesting after you dose.
- Reading and following the labels on the products you actually buy.
- Quarantining and observing new livestock, and deciding what's suitable for your tank.
- Deciding whether a given result makes sense before acting on it.
- Disposing of tank water, plants and livestock responsibly — never into the wild.
- Complying with any local rules on keeping, importing or rehoming aquatic species.
Links to other sites
We link out to retailers, manufacturers and reference sources. Some of those are affiliate links, explained in full in our affiliate disclosure. We don't control other websites and aren't responsible for their content, their products, or their privacy practices — once you leave here, their terms apply.
Content and copyright
The writing, design, code and calculator implementations on this site belong to us. You're welcome to use the tools, quote us with credit and a link, and print or save results for your own use. Please don't republish our articles wholesale, copy the calculators onto another site, or scrape the site automatically.
To be clear about what we're not claiming: the underlying science is public knowledge and nobody owns it. Molar masses, the equation of state for seawater, the practical salinity scale and the published dosing relationships this site is built on are free for anyone to use — it's our particular expression of them that's covered.
Availability
We aim to keep the site up and current, but it's provided as-is. We may change, move or retire tools and articles, and we don't guarantee uninterrupted access. Your saved tank lives in your own browser, so an outage here doesn't take your data with it — and neither does it back it up.
Liability
To the extent the law allows, we're not liable for loss or damage arising from your use of this site — including harm to livestock, damage to a tank or its equipment, water damage, the cost of additives or replacement animals, or losses from acting on a result without checking it.
Nothing in these terms limits or excludes our liability for death or personal injury caused by our negligence, for fraud, or for anything else that can't lawfully be excluded. If you're a consumer, you keep all the statutory rights you have where you live, and nothing here takes them away.
Governing law
These terms are governed by the laws of England and Wales, and disputes fall to its courts. If you use the site as a consumer somewhere else, you keep the protection of any mandatory consumer law that applies where you live.
Changes
We may update these terms as the site grows. The date at the top of this page shows when they last changed materially, and continuing to use the site means the current version applies.
Contact
Questions about these terms: [email protected]. Something here that's factually wrong: [email protected].