If you’re finding black flakes in your Lay-Z-Spa water or you’ve opened your pump to discover the heater rods pushed out of position, you’re almost certainly dealing with a failing 4-tube heater element inside the 2nd generation square HydroJet heater pump.

This is a common issue — and it’s repairable.

Why Am I Getting Black Flakes in My Lay-Z-Spa?

The 4-tube heater elements used in the square HydroJet systems have a black protective coating.

Over time, if water chemistry becomes aggressive (low pH, high chlorine, heavy descaler misuse, or poor alkalinity control), that coating can begin to break down.

When this happens:

• The black coating starts shedding into the water

• Small amounts of water can seep between the heater tubes

• Internal corrosion begins

• Pressure builds between the rods

• The rods can physically push outward

Those black flakes you’re seeing in the spa?
In most cases, that’s your heater element deteriorating.

What Happens When Heater Rods Push Out?

Once corrosion progresses:

• Heater rods can move out of alignment

• Internal electrical connections can weaken

• Loud pops or bangs may occur when the element shorts

• The heater housing can overheat

• In severe cases, the casing can begin to melt

If left too long, it can damage the PCB or cause permanent heater failure.

If you’ve opened your unit and seen rods bulging outward — stop using it immediately.

Important: Not All Black Debris Is the heater.

Sometimes customers are confused:

• Black flakes → usually heater coating failure

• Fine black dust → can sometimes be from liner’s internal pipes breaking down

If the flakes are larger and appear after heating cycles, it’s typically heater related.

If unsure — send us a photo.

Our Upgraded Heater Solution

We stock upgraded 4-tube heater elements designed for the square HydroJet systems.

Options Available:

• Coated version

• Uncoated version

• Both fitted with anti push-out clamps

What Are Anti Push-Out Clamps?

These reinforced clamps are specifically designed to:

• Prevent rods from expanding outward

• Reduce short circuit risk

• Protect the heater casing from burn damage

• Add structural stability under pressure

Even if corrosion begins, the clamps help prevent catastrophic failure.

But Remember — Water Chemistry Still Matters

Upgraded parts are stronger — but no heater will survive aggressive water conditions forever.

To prevent repeat failure:

• Maintain correct pH (7.2–7.6)

• Keep total alkalinity balanced

• Avoid overdosing on chlorine

• Prevent scale buildup

• Avoid tablets

We recommend regular use of:

LayZRepair No Scale & Stain Preventer

This helps reduce mineral buildup inside:

• Heater tubes

• Flow chambers

• Seals

• Pipework

Scale increases internal heat stress and accelerates coating breakdown.

Fix It Properly — Not Just Temporarily

You can purchase:

• Heater element only

• Heater + seal kit

• Full refurbishment kit (complete internal seals + upgraded flow paddle)

If one internal seal has hardened or degraded, chances are the others are in the same condition. A full refurb kit is often the smarter long-term repair.

Symptoms This Page Covers

If you searched for:

• Lay-Z-Spa black flakes in water

• Lay-Z-Spa rods pushed out

• HydroJet heater popping noise

• Heater casing melting

• E02 / E08 after black debris

• A loud bang from the heater pump

This heater element issue is very likely the cause.

Need Help Identifying Your Model?

This issue mainly affects:

• 2nd Gen Square HydroJet Heater Pumps pre 2026

• 4-Tube Heater Element Systems

If you’re unsure which model you have, send us a photo of your heater unit.

Don’t Ignore the Warning Signs

Black flakes today
Rod expansion tomorrow
Short circuit next week

Catching this early can save your PCB and avoid a much more expensive repair.

If you’re seeing signs of heater coating breakdown, upgrade the element and correct your water chemistry before further damage occurs.