Why It Is Not Working: From Symptom to Cause in Scuba Diving
Tank empty first, yo-yo buoyancy, a blocked ear, a racing heart: the diagnostic grid tracing your symptom back to lead, gear, position or CO2 — with the fix.
Sport: Tauchen · Level: Beginner
Introduction
Most of the diving problems that annoy you do not have the cause you suspect. High air consumption is rarely a question of your lungs, a wild up and down rarely a question of skill — and a racing heart at twenty metres often not fear at all.
This is not a technique guide. It says not how it is done right, but what your symptom means — and which of several possible causes applies to you. You read backwards: find the symptom, check the distinguishing feature, apply the fix, go deeper.
Underwater a wrong diagnosis costs more than dives, it costs safety margin. Try to save air by breathing shallower and you accumulate CO2 — and that very CO2 creates the air hunger that makes you breathe even faster [1]. Tinkering with the symptom is more expensive underwater than anywhere else.
What You Need
Your computer profile. Depth, time, on some models tank pressure — your video substitute for everything you missed down there.
A logbook with one honest sentence per dive. Without notes you compare memories, not dives.
A buddy who deliberately swims behind you once. You never see your own position or dangling hoses.
Same gear, same site. Otherwise you are testing the conditions, not yourself.
An honest answer to how you felt before descending. Nervousness is a diagnosis.
Step by Step
The order is not arbitrary: first what you cannot train away, then what you can influence.
1. First Rule Out What Is Not a Technique Problem at All
Pain, dizziness, numbness, hearing loss, unusual exhaustion are not trained away — they need clarification. And one rule sits above it all: keep breathing, always. The regulator delivers gas at ambient pressure; stop breathing while ascending and it keeps expanding in your lungs [2].
2. Then the Gear
Lead, valve, regulator, mask fit, suit. With too much lead you cannot control buoyancy, no matter how good your technique is. A gear fault makes every technique correction invisible.
3. Then Body Position
Only now are trim and fin stroke worth a look. Your position determines drag, and drag determines effort, breathing and air supply. In that chain, not the other way round.
4. Then Breathing and Head
Breathing rhythm and tension come last — both settle by themselves once gear and position are right. Slow, deep breathing measurably lowers ventilation and the work of breathing [3], but only once you have stopped fighting your own lead.
5. One Variable per Dive
Change one thing, not three. Same site, same depth, one sentence in the logbook. Three changes at once give you a feeling, not an insight.
Common Mistakes
"My tank is always the first one empty." Usually too much lead plus a tilted position. Tell them apart: when was consumption high? Evenly across the dive → drag. Only the first ten minutes → nerves. Only the last ten → cold. A jump without extra effort → a leak: check valve and O-ring. Fix: test one cause per dive. More in "Air Consumption and SAC Rate".
"I am constantly bobbing up and down." Usually too much lead, compensated with air in the BCD. Tell them apart: where does it get worse? Wildest near the surface → the air in your BCD, because the volume change is largest up there: six litres up top are only three at ten metres [4]. Sinking as soon as you stop finning → you are flying tilted and holding yourself up with thrust. A few centimetres per breath → all correct, that is your fine adjustment. Fix: weight check at the surface, BCD empty, normal exhale — you should float at eye level. More in "Buoyancy Control Basics".
"One ear will not clear." Usually started too late, not too little force. Tell them apart: Both sides clear at the surface and it only jams from three or four metres → timing and descent speed. The same side jams dry on land too → not a diving problem. Worse day by day over a diving week → irritated mucosa. Fix: go up two metres until the pressure is gone, descend feet first and equalise earlier — never force against a block. More in "Middle Ear Equalization".
"My mask keeps flooding." Usually not the strap, but whatever sits between silicone and skin. Tell them apart: the dry test without the strap. Place the mask on your face and inhale gently through your nose. If it stays on by itself the shape fits — the cause is outside: hair, hood edge, beard line or a strap so tight it warps the silicone. If it falls off without the strap it is the fit, and you do not repair that underwater. Flooding only when you look up or laugh → facial muscles. Fix: strap only tight enough to hold. More in "Basic Equipment: ABC and SCUBA Gear".
"My heart races and I want to go up immediately."Tell them apart: what came first? Air hunger first, usually after exertion or at depth → CO2: gas density rises with pressure, breathing gets measurably harder [3], you breathe shallower, CO2 rises — and CO2 creates exactly the feeling that makes you breathe faster still [1]. Fear first — tight spaces, murky water, buddy out of sight — and the breathing after → stress [5]. The test: hold on, take three or four breaths with the exhale twice as long as the inhale. If the air hunger eases → CO2, if the pressure on your chest stays → your head. Fix: both start the same way — stop, breathe, think, act [6]. More in "The Most Important Rule: Breathing".
"After twenty minutes I am freezing."Tell them apart: when does it start? From minute one → suit too thin or too loose, water is flushing through. Only after twenty to thirty minutes → normal cooling, a question of dive time. Earlier on the second dive → never properly warmed up in the surface interval. Cold hands with a warm core → gloves. Fix: change one thing, start with the hood. More in "Thermal Protection and Energy Conservation".
"When I surface, the boat is never where I expect it."Tell them apart: Off target on the same side every time → systematic: one-sided finning or metal next to the compass (torch, camera housing, knife). Sometimes here, sometimes there → no course held, because buoyancy and navigation at once were too much. If your gut and the compass disagree, the compass is right. Fix: read your outbound heading while descending and work out the return heading. More in "Advanced Underwater Navigation".
"The regulator breathes hard, I have to pull."Tell them apart: from when? Already at the surface → the valve is not fully open or the service is overdue. Only from twenty or thirty metres → physics, not a fault: gas density rises with pressure and so does the work of breathing [3]. Only against current → your ventilation limit, not your gear. Fix: a regulator that breathes hard at the surface does not go in the water. At depth: take the pace out, breathe slower and deeper [3]. More in "Pre-Dive Safety Checks".
Safety Notes
This guide diagnoses, it does not train emergencies. Air sharing, emergency ascents, losing a mask at depth, a failed regulator: not symptoms you look up, but skills practised under supervision — before your next dive, not after it.
These signs are not a technique problem: persistent ear pain, hearing loss, vertigo; a headache that does not clear within an hour on land; tingling, weakness, visual disturbance, exhaustion, joint or chest pain. Which of them is harmless is not yours to decide — nobody assesses decompression sickness in themselves. Fix: medical clarification or your association's emergency hotline, not the next dive.
And the rule above all rules: never hold your breath. Pulmonary barotrauma mostly strikes divers without a detectable risk factor [8]; its most severe form, arterial gas embolism, carries roughly 30 percent mortality and is the second most common cause of diving death after drowning [4]. CO2 retention is detectable in accident cases too [7].
Pro Tip
The most expensive thinking error in troubleshooting is tinkering with the symptom instead of the cause — textbook example: high air consumption. The reflex is to breathe more sparingly. That treats the symptom with exactly what makes it worse: shallow breathing traps CO2, CO2 creates air hunger, air hunger costs air [1].
The counter-move is unspectacular and it works: one sentence per dive in your logbook — symptom, change, result. After ten dives you see a pattern invisible in any single one.
FAQ
Why do I use so much more air than everyone else as a beginner?
Because several small causes multiply, not because your lungs are different. The order to work through: too much lead, tilted position, dangling hoses, tension, cold. The timing reveals the main cause — evenly high means drag, high at the start nerves, high at the end cold.
How do I notice underwater that too much CO2 is involved?
Typically: air hunger that does not match the effort, a dull pressure in your head, the reflex to breathe faster and shallower. Breathing gets harder with depth anyway [3], which feeds the spiral [1]. Counter-move: take the pace out, exhale longer.
Why can I not get buoyancy under control?
Because too much lead is compensated with a lot of air in the BCD — and air changes its volume with depth, lead does not. Check where it gets wildest: near the surface points to the amount of lead [4], at constant depth to body position.
One of my ears will not clear — can I keep descending?
No, and certainly not by force. Go up one or two metres until the pressure is gone and try again feet first. If it still will not clear, the dive is over. Lasting pain, hearing loss or vertigo need medical clarification.
Key Takeaways
Too much lead is the most common hidden cause: it explains yo-yo buoyancy and high air consumption at once — which is why the weight check comes before any technique correction.
A racing heart underwater: if air hunger came first it is usually CO2 [1][3]; if fear came first it is stress [5]. The fix starts the same way for both — stop, breathe, think, act [6].
Pain, dizziness, tingling or hearing loss are not technique errors: they need medical clarification, not training — nobody assesses decompression sickness in themselves.