⚡🐟 Aquarium Power Outage Survival Guide

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🧭 Why It Matters

When power goes out:

• ❌ Filtration stops
• ❌ Aeration stops
• ❌ Circulation stops
• ❌ Heating/cooling stops

Fish rely on dissolved oxygen (DO). Without replenishment, DO can crash to lethal levels in just a few hours depending on biomass, temperature, and backup aeration.

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🧮 Core Formula (simple, effective)

Hours to Critical DO ≈

$\frac{({\text{DO}}_0-{\text{DO}}_{crit})\times V}{\text{Fish demand}+\text{Microbial demand}-\text{Air supply}}$Fish demand+Microbial demand−Air supply(DO0−DOcrit)×V

Where:

• 🪣 V = tank/system volume (L)
• 🌊 DO₀ = starting DO (mg/L)
• ⚠️ DO_crit = danger threshold (~3 mg/L)
• 🐟 Fish demand = biomass (kg) × ~200 mg O₂/kg/h (species & temp dependent)
• 🧫 Microbial demand = detritus bacteria load (0.01–0.05 mg/L/h)
• 🌱 Plant net = +0.02 mg/L/h day, −0.02 mg/L/h night
• 💨 Air supply = battery pump O₂ (~150–600 mg/h per unit)

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📊 Survival Time Examples (400 L system, 2.5 kg plecos at 28 °C)

👉 Light stocking with plants in daylight can last >10 h.

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🧷 Backup Tools

• 🔋 Battery air pumps (2–3 small pumps better than 1 big)
• 🔌 Portable generator (best long-term solution)
• 🔋 USB power banks (with DC air pumps)
• 🧊 Sealed ice bottles (cool water → more O₂ + slower metabolism)
• 🪪 Spare D-cells or car inverter for emergencies

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🌡️ How to Extend Survival

• ❄️ Cool water 1–2 °C → more O₂, slower respiration (+20–30% time)
• 💧 Stop feeding → less fish + microbial demand
• 🧹 Remove detritus → lower microbial load
• 🌊 Maximize gas exchange → lids off, surface turbulence
• 🐠 Reduce biomass load → move big/active fish if needed
• 🌿 Daytime vs Night: plants produce O₂ by day but consume it at night

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📈 Rule-of-Thumb Reference

• 🐟 200 mg O₂/kg/h = average fish respiration at warm temps
• 🌡️ DO saturation at 28 °C ≈ 7.6 mg/L
• 🧫 Dirty tanks (microbial demand 0.05 mg/L/h) crash faster
• ⚠️ Sensitive species: use 4.0 mg/L as critical DO instead of 3.0

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✅ Emergency Checklist

• 🔋 Test battery air pump(s) monthly
• 🧊 Keep ice bottles in freezer
• 🧪 Keep Seachem Prime/Safe for ammonia detox (filtration stalls)
• 🪪 Have spare D-cells / USB packs ready
• 📊 Record stocking biomass & tank volume so you know your “window”

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📂 Tools for You

I prepared an Excel calculator to model your own tanks (volume, fish load, DO, air pumps).
👉 Download the Estimator

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⚡🐠 Bottom Line:
At heavy stocking, you may have only 3–5 hours without backup air.
A strong battery pump doubles or triples that window, while a generator makes survival indefinite.