pH Shock酸碱震荡

Symptoms

• Rapid breathing, darting or loss of balance, with spinning and rolling
• Colour draining away to pale or dark, with heavy slime production
• Abnormal gill movement, clamped fins, and fish crowded motionless in a corner
• Symptoms appear within hours of a water change, fertiliser dose or CO2 adjustment

Treatment, in order

1. 1 · Water changeStop every source of the swingTurn off CO2, pause fertiliser dosing and stop further water changes; repeated interventions during a swing only deepen the damage, so stop first.
2. 2 · Water changeCorrect slowly rather than forcing itBring pH back toward its original value by no more than 0.2 per hour; slower is safer. A second swing caused by chemical pH adjusters is usually more lethal than the original deviation.
3. 3 · ObserveBoost aeration and leave the fish aloneRun aeration at full, dim the light, do not feed and do not net the fish - let them recover in a low-stress environment, since gills and slime coat need time to repair.
4. 4 · Water changeSet up slow water changes and drip acclimationFrom then on change smaller volumes more often and add new water by drip or trickle; measure pH, KH and temperature of the new water beforehand.
5. 5 · MedicationRaise KH to stabilise bufferingWhen KH is low, raise carbonate hardness slowly at the label dose so pH stops drifting with minor disturbances; also do this in stages to avoid another swing.
6. 6 · ObserveMonitor for 24-48 hoursTest pH, KH and ammonia for two days to confirm a flat curve; if skin lesions or white spots appear, they are usually secondary infections after the shock weakened the fish.

Medications and cautions

pH buffers (sodium bicarbonate or branded buffers)

Use only after KH is confirmed low and the original cause is removed, adding it in stages at the label dose; raising pH quickly causes a second shock, so never do it in one step.

Prevention

• Test pH, KH and temperature of new water before changes and split them when the gap is large
• Keep KH in a stable range so pH has buffering
• Fit a solenoid and timer to the CO2 system so it cannot run away at night
• Do not force pH with chemicals - stability matters more than chasing a number

Frequently asked questions

What are the symptoms of pH Shock?

Rapid breathing, darting or loss of balance, with spinning and rolling; Colour draining away to pale or dark, with heavy slime production; Abnormal gill movement, clamped fins, and fish crowded motionless in a corner; Symptoms appear within hours of a water change, fertiliser dose or CO2 adjustment. It usually starts with: A large water change where the new water differs in pH by more than 0.5; A CO2 system failing or shutting off overnight, swinging pH within a night; Substrate or rock slowly shifting hardness and pH until the drift suddenly shows; Low KH with little carbonate buffering, leaving pH easily knocked off course.

How do you treat pH Shock?

In order: 1. Stop every source of the swing (Turn off CO2, pause fertiliser dosing and stop further water changes; repeated interventions during a swing only deepen the damage, so stop first.) 2. Correct slowly rather than forcing it (Bring pH back toward its original value by no more than 0.2 per hour; slower is safer. A second swing caused by chemical pH adjusters is usually more lethal than the original deviation.) 3. Boost aeration and leave the fish alone (Run aeration at full, dim the light, do not feed and do not net the fish - let them recover in a low-stress environment, since gills and slime coat need time to repair.) 4. Set up slow water changes and drip acclimation (From then on change smaller volumes more often and add new water by drip or trickle; measure pH, KH and temperature of the new water beforehand.) 5. Raise KH to stabilise buffering (When KH is low, raise carbonate hardness slowly at the label dose so pH stops drifting with minor disturbances; also do this in stages to avoid another swing.) 6. Monitor for 24-48 hours (Test pH, KH and ammonia for two days to confirm a flat curve; if skin lesions or white spots appear, they are usually secondary infections after the shock weakened the fish.)

Is pH Shock contagious, and how urgent is it?

Contagion: not contagious. Severity: severe. Cause: water quality. Urgent. A severe swing can kill within hours, though most fish recover within a day or two once pH is stable; the key is to stop disturbing the water.

What medication treats pH Shock?

pH buffers (sodium bicarbonate or branded buffers): Use only after KH is confirmed low and the original cause is removed, adding it in stages at the label dose; raising pH quickly causes a second shock, so never do it in one step.

Will treating pH Shock affect the rest of the tank?

Treatment here is water quality, temperature stability and supportive care rather than an invertebrate-toxic medication, so the fish does not have to come out of a reef tank.