# AquaCalc
> A free, privacy-first water chemistry toolkit for planted aquarium enthusiasts.
> Thirteen tools covering CO₂ monitoring, RO water mixing, fertiliser dosing, water change planning, tank volume, substrate, filter capacity, CO₂ cylinder runtime and more.
> No account required. All data saved locally per tank profile. Based in the UK.
> Full article text in Markdown: https://www.aquacalc.uk/llms-full.txt (individual articles also at <article-url>.md)

## Tools
The dashboard and all calculators are at https://www.aquacalc.uk/dashboard/
All calculators hub: https://www.aquacalc.uk/tools.php
Tank volume calculator (rectangle, bowfront, hex, corner, cylinder, sphere — adjusts for substrate, hardscape and filter volume): https://www.aquacalc.uk/tank-volume-calculator.php
Substrate calculator (volume, weight, bag count for ADA, Tropica, Fluval Stratum, UNS Controsoil and more; flat and sloped layouts): https://www.aquacalc.uk/substrate-calculator.php
CO₂ cylinder runtime estimator (days remaining, run-out date, reorder reminder from weight, bubble rate and diffuser type): https://www.aquacalc.uk/co2-cylinder-calculator.php
Filter capacity calculator (biological surface area and fish load by media type — based on aquariumscience.org data): https://www.aquacalc.uk/filter-capacity-calculator.php
Drop checker colour guide (personalised colour reference by KH; flags visually indistinguishable CO₂ ranges): https://www.aquacalc.uk/drop-checker-guide.php
Fish species lookup (temperature, pH, hardness, tank size — data from FishBase): https://www.aquacalc.uk/fish-lookup.php
Aquarium heat forecast — 14-day temperature outlook with Good / Warming / Extreme risk indicators for any location worldwide: https://www.aquacalc.uk/aquarium-heat-forecast.php

## Science articles
In-depth guides on aquarium chemistry, biology, and planted tank practice.

- CO₂ boundary layer physics — why 30 ppm CO₂ in bulk water is not 30 ppm at the leaf surface, diffusion rates in water vs air, boundary layer thickness, circulation and flow implications for planted tanks: https://www.aquacalc.uk/blog/co2-leaf-boundary-layer
- Active substrates and CEC — cation exchange capacity, how volcanic soils buffer pH and release nutrients, why hard water degrades CEC faster, what happens as aquasoil ages: https://www.aquacalc.uk/blog/aquarium-substrate-cec
- Aquarium surface agitation — gas transfer physics (surface renewal theory), when flat surfaces are safe in planted tanks vs. when they risk overnight hypoxia, the CO₂ timer trap: https://www.aquacalc.uk/blog/aquarium-surface-agitation
- Dissolved oxygen in aquariums — saturation thresholds, diurnal DO cycle in planted tanks, what chronic hypoxia does to fish immunity and growth: https://www.aquacalc.uk/blog/dissolved-oxygen
- KH, GH and the CO₂–pH triangle — carbonate buffering chemistry, why KH (not GH) controls pH stability, where the CO₂ triangle breaks down, pH crashes in soft water: https://www.aquacalc.uk/blog/kh-co2-ph
- Heatwave and heat stress — the physics of how outdoor temperatures heat tank water, the oxygen squeeze (Henry's Law + Q10 metabolic rate), ammonia toxicity at high temperature, and evidence-graded coping strategies: https://www.aquacalc.uk/blog/heatwave
- Plant melt — why emersed-grown and tissue culture plants dissolve after planting, what heterophylly is, and when to worry vs. wait: https://www.aquacalc.uk/blog/plant-melt
- Water changes — frequency, volume, nitrate science, and the "large water change kills fish" myth: https://www.aquacalc.uk/blog/water-changes
- Lily pipe placement — gyre geometry, Coanda effect, inlet/outlet positioning for whole-tank CO₂ distribution: https://www.aquacalc.uk/blog/lily-pipe-placement
- Black beard algae — CO₂ instability as cause, H₂O₂ and glutaraldehyde treatments, what is evidence vs. hypothesis: https://www.aquacalc.uk/blog/black-beard-algae
- Aquarium flow — why the 10× turnover rule was never about plants, what flow actually does for CO₂: https://www.aquacalc.uk/blog/aquarium-flow
- CO₂ stability — what "stable CO₂" really means and why a fixed 30ppm target is a myth: https://www.aquacalc.uk/blog/co2-stability
- Comammox bacteria — the organism that completes the nitrogen cycle in one step, and what it means for cycling: https://www.aquacalc.uk/blog/comammox
- Chlorine and chloramines — why tap water is more acutely dangerous than ammonia, and how to make it safe: https://www.aquacalc.uk/blog/chlorine
- UV sterilisers and inactivation — what UV actually kills (Cryptosporidium, algae, bacteria) and what it doesn't (Adenovirus, encysted stages, dissolved chemistry), based on Hijnen et al. (2006): https://www.aquacalc.uk/blog/uv-steriliser-science
- UV steriliser sizing and dose — flow rate as the key variable (not wattage), dose requirements per organism, lamp aging, turbidity effects: https://www.aquacalc.uk/blog/uv-steriliser-sizing
- Nitrogen waste in closed aquariums — 60–90% dissolved as ammonia, nitrification chain, why nitrate accumulates, what plants and water changes actually do, based on van Rijn (2013): https://www.aquacalc.uk/blog/nitrogen-waste-aquarium
- Science-backed guide to iron chelation in planted aquariums: why Fe-EDTA fails above pH 7.0, how Fe-DTPA and Fe-EDDHA differ, and how to choose the right chelate for your tank's pH range.: https://www.aquacalc.uk/blog/chelated-iron-aquarium
- Hornwort (Ceratophyllum demersum) plant profile covering its exceptional growth rate, water-purifying properties, floating vs anchored placement, allelopathic effects, and why it sheds needles.: https://www.aquacalc.uk/plants/hornwort
- Pogostemon helferi (Downoi) care guide covering star-shaped rosette growth, Thai river origins, flow requirements, CO2 recommendations, and foreground placement: https://www.aquacalc.uk/plants/pogostemon-helferi
- Bacopa caroliniana care guide covering slow steady growth, lemon monoterpene scent, low light tolerance, stem trimming and replanting, and comparison with faster stem plants: https://www.aquacalc.uk/plants/bacopa-caroliniana
- Hygrophila polysperma care guide covering extreme adaptability, fast growth rate, pink variegated form, invasive status in some regions, and maintenance: https://www.aquacalc.uk/plants/hygrophila-polysperma
- Water wisteria (Hygrophila difformis) care guide covering leaf heterophylly, fast growth, low light tolerance, and nutrient stripping: https://www.aquacalc.uk/plants/water-wisteria
- Tiger lotus (Nymphaea zenkeri) care guide covering bulb planting, surface pad management, red vs green forms, and why trimming keeps it compact: https://www.aquacalc.uk/plants/tiger-lotus
- Bucephalandra care guide covering rheophyte origins, iridescent leaf coloration, hardscape attachment, slow growth rate, and variety overview: https://www.aquacalc.uk/plants/bucephalandra
- Alternanthera reineckii care guide covering red coloration, light and phosphate requirements, stem trimming, and variety differences (Mini vs standard): https://www.aquacalc.uk/plants/alternanthera-reineckii
- Staurogyne repens care guide covering foreground placement, trimming technique, moderate light needs, and comparison with carpeting alternatives: https://www.aquacalc.uk/plants/staurogyne-repens
- HC Cuba (Hemianthus callitrichoides) care guide covering carpet growth, high-light CO2 requirements, substrate selection, and melting after purchase: https://www.aquacalc.uk/plants/hc-cuba

## Plant Insights
Science-grounded species profiles covering care requirements, light, CO2, substrate, and what makes each plant thrive or struggle.
Plants hub: https://www.aquacalc.uk/plants/

- Amazon Sword (Echinodorus grisebachii 'Bleherae') care guide — large rosette from South America, heavy root feeder (root tabs needed in inert substrates), low to medium light, no CO2 required, moderate growth, emersed leaves die off after purchase which is normal, iron deficiency causes yellow leaves with green veins: https://www.aquacalc.uk/plants/amazon-sword
- Anubias barteri var. nana care guide — rheophyte epiphyte from West Africa, very low light, no CO2 needed, attaches to hardscape, never bury rhizome: https://www.aquacalc.uk/plants/anubias-nana
- Cryptocoryne wendtii care guide — Sri Lanka endemic, low-medium light, no CO2 required, root feeder, crypt melt is leaf response not death: https://www.aquacalc.uk/plants/cryptocoryne-wendtii
- Eleocharis parvula (Dwarf Hairgrass) care guide — foreground carpet plant, needs high light at substrate level and CO2 injection to spread; etiolates without sufficient light: https://www.aquacalc.uk/plants/eleocharis-parvula
- Java Fern (Microsorum pteropus) care guide — attach to hardscape not substrate, very low light, no CO2 needed, slow grower, propagates from rhizome division: https://www.aquacalc.uk/plants/java-fern
- Java Moss (Taxiphyllum barbieri) care guide — attaches to any surface, extremely low light, no CO2 needed, fast grower, useful for fry refuges and moss walls: https://www.aquacalc.uk/plants/java-moss
- Ludwigia repens care guide — fast-growing red stem plant from North America, no CO2 required, red colour driven by light intensity and iron availability (not CO2), leaf undersides always red, moderate to high light needed, fast grower requiring regular trimming, propagate by stem cuttings: https://www.aquacalc.uk/plants/ludwigia-repens
- Monte Carlo (Micranthemum tweediei) care guide — fine-leafed carpet plant from Argentina, moderate to high light needed at substrate level, CO2 strongly recommended for lateral spreading (grows upward without it), fine aquasoil substrate required, plant deeply to prevent floating, trim regularly: https://www.aquacalc.uk/plants/monte-carlo
- Rotala rotundifolia care guide — colour shifts green to red with light/CO2/phosphate; CO2 injection needed for red colour; stem cuttings for propagation: https://www.aquacalc.uk/plants/rotala-rotundifolia
- Vallisneria spiralis care guide — fast-growing background plant, tolerates hard water, killed by glutaraldehyde liquid carbon products (Easycarbo/Excel): https://www.aquacalc.uk/plants/vallisneria-spiralis
- Science-backed guide to feeding aquarium fish: food types (dry, frozen, live, vegetable), calculating daily rations by body weight, Q10 temperature effects, ammonia production formula (TAN = food x protein% x 0.136), nitrogen budget in planted tanks, and how overfeeding drives algae in CO2-injected setups.: https://www.aquacalc.uk/blog/fish-feeding

## Other pages
- Planted tank guide (beginner overview): https://www.aquacalc.uk/guide.php
- FAQ: https://www.aquacalc.uk/faq.php
- Community resources: https://www.aquacalc.uk/resources.php
- About AquaCalc: https://www.aquacalc.uk/about.php
- Disclaimer (tool accuracy, limitations, no liability for livestock): https://www.aquacalc.uk/disclaimer.php

## Feeds and metadata
- RSS feed: https://www.aquacalc.uk/feed.xml.php
- Sitemap: https://www.aquacalc.uk/sitemap.xml.php