Step-by-step
Step 1: Test nitrateReef target: 5-10 ppm. FOWLR/freshwater target: 10-20 ppm. Above 40 = intervention needed. Above 80 = sensitive species at risk.
Step 2: Reduce feedingExcess food rots into nitrate. Cut feeding by 30% for 2 weeks. Skip a feeding day per week. Most tanks are overfed.
Step 3: Increase water change frequencyBump from 25% weekly to 30-40% weekly until nitrate drops. Each 25% change drops nitrate by 25%.
Step 4: Add a refugium with chaetomorphaSaltwater: chaeto in a sumped refugium under reverse-cycle lighting. Consumes nitrate + phosphate as it grows. Harvest 1/3 every 2-3 weeks to export nutrients.
Step 5: Add live plants (freshwater)Fast-growing stems consume nitrate aggressively. Hornwort, water sprite, anacharis, water lettuce (floating). Trim weekly to remove the absorbed nitrate.
Step 6: Run biopelletsSaltwater advanced: pellets in a fluidized reactor drive bacterial growth that consumes N + P. Pair with a strong skimmer to export the bacteria.
Step 7: Vodka dosing (ULNS)Expert reef systems only. Daily dose of vodka feeds bacteria that consume N + P. Highly effective for SPS coloration. Requires precise testing - excess can crash the tank.
Frequently asked questions
What causes high nitrate?
Nitrogen waste from fish + uneaten food + decaying organics. The bio-filter converts ammonia → nitrite → nitrate; nitrate accumulates without removal.
Is high nitrate dangerous?
Above 40 ppm stresses SPS coral + sensitive fish. Above 80 ppm causes long-term organ damage. Above 100 = many species die within weeks.
How fast can I lower nitrate?
Don't target more than 25% reduction per day to avoid parameter shock. Sustained 50% weekly water changes can drop nitrate from 80 to 20 in 2-3 weeks.