{"uid":"cap_GLGu3jrVSurX_NXVG7uaY","slug":"pet-care-calc-aquarium-water-change-nitrate-calculator-4ac36ea5","name":"Pet Care Calc – Aquarium Water Change Nitrate Calculator","description":"Nitrate left after partial water changes, changes needed to reach a target, and the litres or gallons per change.","url":"https://pet-calc.x402tookit.com/water-change?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET"],"type":"string"},"queryParams":{"type":"object","required":["tankVolume","changePercent","startPpm"],"properties":{"tapPpm":{"type":"number","description":"Concentration in the replacement water (default 0; tap water can carry nitrate)"},"changes":{"type":"integer","description":"A number of changes to project (default 1)"},"startPpm":{"type":"number","description":"Starting concentration, for example nitrate in ppm (mg/L)"},"targetPpm":{"type":"number","description":"A target concentration, to count the changes needed"},"tankVolume":{"type":"number","description":"Tank water volume (gallons or litres; the answer uses the same unit)"},"changePercent":{"type":"number","description":"Share of the water replaced per change, 1 to 90 percent"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object","properties":{"asOf":{"type":["null","string"]},"source":{"type":["null","string"]},"tapPpm":{"type":["null","number"]},"reasons":{"type":["array","null"],"items":{"type":"string"}},"summary":{"type":["null","string"]},"verdict":{"type":["null","string"]},"degraded":{"type":["boolean","null"]},"disclaimer":{"type":["null","string"]},"notChecked":{"type":["array","null"],"items":{"type":"string"}},"projection":{"type":["array","null"],"items":{"type":"object","properties":{"ppm":{"type":["null","number"]},"change":{"type":["null","number"]}}}},"afterChanges":{"type":["null","number"]},"fractionKept":{"type":["null","number"]},"percentReduction":{"type":["null","number"]},"concentrationAfter":{"type":["null","number"]},"changesNeededForTarget":{"type":["null","number"]},"volumeChangedPerWaterChange":{"type":["null","number"]}}}}}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.02","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.02/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_FgHJ-9UkgHv4hOVvV0QEb","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.02","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Calculates nitrate concentration remaining after partial water changes, how many changes are needed to reach a target PPM, and the volume of water exchanged per change.","exampleAgentPrompt":"My 75-gallon aquarium currently has 80 ppm nitrate and I do 30% water changes — my tap water has 5 ppm nitrate. How many changes will it take to get below 20 ppm, and how many gallons am I changing each time?","exampleUseCases":[{"title":"Reducing dangerously high nitrate","prompt":"My fish tank is 100 litres and the nitrate is at 120 ppm — that's way too high. If I do 25% changes with tap water that has 0 ppm nitrate, how many changes do I need to get below 20 ppm?"},{"title":"Planning a routine maintenance schedule","prompt":"I have a 55-gallon tank with nitrate sitting at 40 ppm. I do weekly 20% water changes and my tap reads about 3 ppm nitrate. Can you project the nitrate level after each of the next 5 changes?"},{"title":"Sizing a single water change to hit a target","prompt":"My 30-litre nano tank has 60 ppm nitrate and I want to do just one water change to bring it under 25 ppm. My tap is 0 ppm — what percentage change do I need, and what's the volume I'll be replacing?"}],"resultDescription":"Returns the nitrate concentration after the specified number of water changes, the fraction of water kept, the percent reduction achieved, the volume of water changed per change, how many changes are needed to reach the target PPM, and optionally a per-change projection array showing PPM at each step. Also includes contextual summary text, disclaimer, and metadata fields.","failureModes":["Missing required parameters (tankVolume, changePercent, startPpm) returns a validation error","changePercent outside 1–90 range may return an error or unexpected result","Negative or zero tankVolume causes computation failure","Network or payment (x402) failure results in HTTP 402 or 5xx with no data","If targetPpm is not supplied, changesNeededForTarget will be null"],"whenToPreferThis":"Choose this endpoint when you need to compute aquarium nitrate dynamics from partial water changes — specifically when the user has a tank volume, a known starting nitrate level, and a change percentage, and wants either a projection over multiple changes or the number of changes to reach a safe level. Prefer over generic chemistry calculators because it natively handles tap-water nitrate offsets, multi-change projections, and outputs volume in the user's own units (gallons or litres).","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-30T00:30:45.873Z","isFirstParty":false,"canonicalSlug":"pet-care-calc-aquarium-water-change-nitrate-calculator-4ac36ea5"}