Algae in the reservoir: causes and prevention
Algae grows wherever light hits nutrient solution. It swings your pH, depletes overnight oxygen, and clogs drip lines. Light exclusion solves 90% of it.
Calculators and guides for the water-and-light side of growing things.
Freshwater tanks, hydroponics, aquaponics, and off-grid solar to power any of it. Calculators that update as you type, reference that shows its work.
Topics
Four topics. Fish tanks, soilless growing, the combination of both, and the solar panels that keep it all running.
Aquariums
Freshwater fishkeeping, planted tanks, and the gear that keeps them alive.
Explore aquariums →Hydroponics
Soilless growing for food crops. EC, nutrients, lighting, the works.
Explore hydroponics →Aquaponics
Where fish feed plants and plants clean water. The whole reason this site exists.
Explore aquaponics →Solar
Off-grid power sizing for pumps, lights, heaters, and the rest of a homestead setup.
Explore solar →Tools
Browser-side calculators. No sign-in, no submit button, results stay local to your machine.
Tank volume
Rectangular, bowfront, cylindrical, hex, and custom shapes. Reports gallons (US and imperial) and liters.
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Fish stocking calculator
Bioload, schooling minimums, and weekly water change estimates. Replacement for the ancient AqAdvisor.
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Water change
How much water to swap to bring nitrate, TDS, or any dilutable parameter down to a target value.
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Heater wattage
How many watts of heating you need. Quick rule-of-thumb mode or physics-based detailed mode for non-standard tanks and unusual rooms.
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Substrate volume
Substrate volume for a tank footprint plus depth. Estimates bag counts for common aquasoil, sand, and gravel products.
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Tank weight calculator
Total weight on your floor: water, glass, substrate, hardscape, and stand. For anyone worried about putting a tank upstairs.
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Recent articles
Long-form explainers and reference reading.
Why your angelfish ate your neons
Angelfish are cichlids. Neon tetras fit in their mouths. The only question is when, not if. How predation thresholds work and which tankmates survive.
The actual cost of keeping a fish tank for a year
A 200-liter community tank costs $150-250 per year to run after the initial setup. Electricity is the biggest line item. Here's the full breakdown by tank size.
Aquaponics system maintenance calendar
Daily, weekly, monthly, and seasonal tasks in one reference. Print it, stick it on the wall next to the system, and check things off.
Aquaponics operating costs: a real spreadsheet
Feed, electricity, water, and supplements by system size. What a small backyard system actually costs per month, with numbers instead of vague estimates.
Aquaponics permits: what you need before selling fish or produce
Aquaculture licenses, food safety rules, and species restrictions vary by state. Eating your own fish is different from selling them. What to check before building.