Technical · updated 03 August 2026
Ozone is one of the strongest oxidisers you can make at home. It attacks the carbon double bonds that most flexible plastics and rubbers are built from. Use the wrong tubing and it hardens, cracks, sheds particles and leaks, while the degradation products end up in whatever you are treating.
Safe in the ozone path
| Material | Use | Notes |
|---|---|---|
| Silicone | Tubing | The usual choice. Flexible, good ozone resistance. Still replace periodically. |
| PTFE (Teflon) | Tubing, tape, seals | Best resistance available. Stiffer and pricier than silicone. |
| Glass / quartz | Cells, vessels, diffusers | Completely inert. Quartz is why good cells are quartz. |
| 316 stainless | Fittings, luer locks | The right stainless. 304 is less resistant. |
| Kynar / PVDF | Fittings | Good where a rigid plastic fitting is needed. |
Not safe
| Material | What happens |
|---|---|
| Natural rubber, latex | Degrades fast. Cracks and crumbles. |
| Vinyl / PVC | Hardens and yellows. Common on cheap kits, and wrong. |
| Neoprene, EPDM, Buna-N | Swell and perish. |
| Polyurethane | Breaks down. |
| Standard silicone sealant | Not the same as silicone tubing. Do not use it in the gas path. |
Oxygen adds a second constraint
Anything on the oxygen side must be completely free of oil and grease. In an oxygen-enriched atmosphere, hydrocarbons can ignite violently. Do not lubricate oxygen fittings, do not handle them with oily hands, and use oxygen-rated components.
When to replace
Silicone tubing is a consumable. Replace it when it stiffens, discolours, smells odd, or every few months under regular use, whichever comes first. Diffuser stones clog gradually; a stone producing visibly coarser bubbles than when new is due for replacement.
Replacement tubing and diffusers.
Equipment information only. Nothing here is medical advice.