Introduction – The Big Fork in the Road

Once you’ve completed PADI Tec40 or Tec45, you’re standing at the same crossroads every technical diver eventually faces:

Do I continue on open circuit and go trimix?
Or should I move onto a rebreather (CCR) now?

Most divers don’t know which path fits their long-term goals. This guide breaks it down based on real experience in Malta’s wreck environment.

Why This Question Matters

Both trimix and CCR are incredible tools – but they serve different purposes.

The right choice depends on:

• Your goals
• Your budget
• How often you plan to dive
• Whether you want to build towards 100 m+ wreck dives
• How much you enjoy equipment and planning

Let’s break it down into the realities, not the marketing.

Option 1 – Go Trimix First (Open Circuit)

What It Is

Trimix training continues your OC journey into deeper and safer profiles by replacing nitrogen with helium.

Typical depth ranges:

• Tec50 Trimix: ~50–60 m
• Full Trimix: 70–100 m+

Why Choose Trimix First

1. You build problem-solving discipline

Open-circuit trimix forces you to:

• Track multiple gases
• Plan bailout precisely
• Handle failures with increasing decompression
• Maintain rock-solid buoyancy under narcosis reduction

It builds strong mental discipline for later CCR work.

2. Zero new life-support systems to learn

You stay with what you know:

• Twinset
• Stages
• Gas switches
• Existing protocols

This removes cognitive load compared to jumping straight into a rebreather.

3. Ideal if you dive only a few big trips a year

Trimix is straightforward for:

• Malta holidays
• Red Sea trips
• Occasional deep wreck missions

You don’t lose currency like you might on CCR if you take long breaks.

4. Cheaper upfront

No unit purchase, no electronics. Just:

• Twinset + regs
• Two stage cylinders
• Trimix training

Much lower barrier to entry.

Limitations of Trimix

• Gas costs add up, especially 60–90 m
• You’re carrying a lot of cylinders
• Short bottom times compared to CCR
• Logistics are heavy for multiple deep dives in a week

Trimix is amazing, but at some point you hit its practical ceiling.

Option 2 – Go Rebreather (CCR) First

What It Is

A rebreather recycles your gas, optimises PO₂ and dramatically improves efficiency.

You’re specifically training on the Hollis Prism 2 CCR.

Why Choose CCR First

1. Much longer bottom times

On a 70–90 m wreck, you can spend:

• Twice as long (and often more)
• With manageable deco
• Without mountains of OC gas

This is the biggest reason divers move to CCR early.

2. Huge gas savings

You’re not burning trimix every minute – you’re recycling it.
This makes deep diving far more affordable long-term.

3. Reduced narcosis

Running a consistent high PO₂ means you stay sharper at depth.
Less low-viz “fog”, better awareness.

4. Real progression to expedition-level diving

If you ultimately want to dive:

• HMS Southwold (70–73 m)
• HMS Stubborn (~55 m)
• Schnellboot (~65+ m)
• ORP Kujawiak / HMS Oakley (~100 m class)
• Or eventually Brittanic (120 m)

…CCR is the platform.

5. Modern training is safer and more structured

The Prism 2 is one of the most stable, predictable units for new CCR divers.

Training focuses on:

• Loop failures
• Bailout
• Realistic problem-solving
• Team behaviour

Not on “unit tricks” or shortcuts.

Limitations of CCR

• Higher upfront cost
• Electronics require discipline
• You must stay current
• More time spent maintaining the unit
• Bailout needs to be taken seriously

CCR requires a mindset shift – but for many divers it becomes their main tool for life.

Trimix vs CCR – Which Path Fits Your Goals?

Here is the straightforward comparison:

If your goals are 40–55 m wrecks, a few trips per year → Trimix first

You’ll benefit from:

• Simple logistics
• Strong OC skill refinement
• Lower initial investment

Perfect if you’re still exploring the idea of tech.

If your goals are 60–100 m wrecks → CCR first

You’ll benefit from:

• Longer bottom times
• Lower helium costs
• Greater capability and stability
• A platform you can grow with for years

If you know you want deep wreck experience, go CCR early.

If you’re not sure yet → Do Tec40/Tec45, then decide

Tec40 + Tec45 give you:

• Full foundations
• True deco experience
• Team protocols
• Gas switch discipline

You’ll know after Tec45 whether OC trimix or CCR excites you more.

What I Recommend as an Instructor (Realistically)

After 500+ hours on the Hollis Prism 2 and thousands of OC dives:

Best progression for most divers aiming beyond 60 m:

1. Twinset + Intro to Tec
2. Tec40 + Tec45
3. Move to CCR (Prism 2)
4. CCR 40 → CCR 60 → CCR 100
5. Optional: OC trimix as a cross-training tool

This gives you:

• Strong OC discipline
• Early CCR experience
• A safe path to serious wreck diving
• The ability to do long deep dives properly

This is the pathway I used myself.

Training in Malta – Why It Works for Both Paths

Malta delivers perfect environments for both:

Trimix training

• 45–60 m wrecks from shore
• Clear drills on the Cirkewwa platforms
• Smooth transitions from Tec45 to Tec50

CCR training

• Controlled shallows for loop work
• Deep walls and wrecks for 60–100 m progression
• Stable conditions for multi-day courses
• Minimal currents, predictable weather

Few places in the world offer such clean progression.

Final Decision Guide – Quick Answers

Go Trimix First If…

• You want to improve OC skills
• You dive occasionally
• You prefer a lower upfront cost
• You want to take it slow and steady

Go CCR First If…

• You want 60–100 m wreck capability
• You want longer bottom times
• You’re tired of helium bills
• You want a long-term deep diving platform

Unsure? Start with Tec40/45.

You will know exactly which path feels right.