Free Aquaponics Sizing Calculator
Balance your ecosystem using the science-backed UVI feed rate ratio: calculate daily feed, fish stocking biomass, and plant grow bed surface area.
🌱 Plant Canopy & Crop Demands
📊 System Sizing & Feed Requirements
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The Science of Aquaponics Sizing
Beginners frequently assume aquaponics balance is calculated by counting fish per plant. In reality, Dr. James Rakocy at the University of the Virgin Islands (UVI) established that daily feed input is the true driving variable of the system.
The UVI Feeding Rate Ratio
Why Underfeeding and Overfeeding Both Cause Failure
If daily feed is too low ($<30\text{ g/m}^2$), plants starve from iron, potassium, and nitrogen deficiencies, turning yellow. Conversely, if feed is too high ($>100\text{ g/m}^2$), unabsorbed organic solids overwhelm the biofilter, spiking toxic ammonia and suffocating fish.
Frequently Asked Questions
Why do fruiting crops require nearly double the fish feed of lettuce?
Leafy herbs and lettuces only require moderate nitrate (N) levels to develop leaves. Fruiting plants (tomatoes, bell peppers, strawberries) require massive quantities of potassium (K), phosphorus (P), and calcium (Ca) to set flowers and swell fruit.
What water pH should an aquaponics system target?
Aquaponics requires a compromise pH between 6.8 and 7.2. Fish prefer 6.5 to 8.0, nitrifying bacteria function best above 7.5, and plants absorb micronutrients best below 6.5. A pH of 6.8 to 7.0 harmonizes all three living organisms.
How much water volume should be pumped per hour?
The entire fish tank volume should circulate through the solid filter and grow beds at least once per hour (1x tank turnover per hour). For a 150-gallon fish tank, use a pump rated for at least 150 to 250 GPH at head height.