Liquid vs Strip
Liquid test kits (API Master Kit) are accurate and cheap per test. Slightly time-consuming.
Test strips are faster but less accurate. Keep strips for quick checks, liquid for decisions.
Parameter Guide
Ammonia: 0 ppm always. Any reading means cycle crash.
Nitrite: 0 ppm always. Any reading is dangerous.
Nitrate: under 20 ppm ideal, under 40 acceptable. Above 40 indicates overdue water change.
pH: species-specific. Stability matters more than exact number.
Frequency
Cycling tanks: daily ammonia and nitrite until zero.
Established tanks: monthly full panel.
After changes (new fish, equipment): weekly for 4 weeks.
When any fish shows distress: immediate full test.
Action Levels
Ammonia 0.25+ ppm: immediate 50% water change.
Nitrite 0.25+ ppm: 50% water change, reduce feeding.
Nitrate 40+ ppm: water change now, increase frequency.
pH swing 0.5+ in 24 hours: investigate source water and buffering.