Decision essentials
Key points
An air leak may not leak water outward.
The suction side is most sensitive.
Cavitation reduces flow and can damage.
Filter troubleshooting
Use timing as evidence
Immediate fading bubbles suggest residual air; rhythmic or continuous bubbles suggest entry.
A near-surface intake can vortex, while clogged foam lowers local pressure.
Filter troubleshooting
Seal before purging again
Reseat dry connections, raise level and remove kinks. Purge only as instructed.
A gravel-like rotor sound requires shutdown.
From evidence to action
Decision matrix
| Situation | What to do | Why |
|---|---|---|
| Only after service | Purge and observe | Residual air |
| Continuous bubbles | Inspect suction side | Air can enter without water loss |
| Visible intake vortex | Raise level or lower intake | Stops air draw |
Check the result
Record the symptom and time before intervening. Repeat the same check afterwards, watch breathing and behaviour, and keep a timeline; if the problem worsens, prioritise safety and reassess the diagnosis. For “Filter blowing air or microbubbles: trapped air, suction leak or cavitation”, use cavitation reduces flow and can damage as the final article-specific check.
Evidence
Sources and scope
Sources include institutions, technical studies and manufacturers. Chezur separates established mechanisms from editorial decisions for home aquariums.
- EHEIM — Operating and troubleshooting manual manufacturer
- University of Florida IFAS — Pumps and total head institution