Lo-Chlor is Australia's most trusted specialist pool and spa chemical manufacturer globally recognised and exporting to 25+ countries. Their range covers algaecides, clarifiers, phosphate removers, stain treatments, stabilisers, spa care, equipment aids and more, every product formulated for Australian water chemistry and climate.
Lo-Chlor Instant Sunscreen is a liquid cyanuric acid (CYA) chlorine stabiliser that slows the degradation of chlorine by UV — extending the effective life of your chlorine in outdoor pools. The 2.5L is the most popular size for standard residential pools needing regular stabiliser top-ups after backwashing.
UV light from the sun is the single biggest consumer of pool chlorine in outdoor pools. Without stabiliser, chlorine degrades rapidly — losing up to 90% of its effectiveness within a few hours of direct sunlight. Cyanuric acid forms a protective bond with chlorine molecules, shielding them from UV breakdown and dramatically extending how long each dose remains active.
Lo-Chlor Instant Sunscreen details
Liquid cyanuric acid — no pre-dissolving, no skimmer sock required
Works from the moment it is added — unlike dry granular CYA
Slows UV degradation of chlorine, extending effective life
Concentrated liquid formulation
2.5L
Compatible with all pool types and sanitiser systems
The ideal cyanuric acid range for outdoor chlorine pools is 30–50 ppm. Test CYA levels before dosing — too much stabiliser (above 100 ppm) actually reduces chlorine effectiveness by over-stabilising it. For salt pools, the target range is typically 50–80 ppm. For pools using AquaFresh non-chlorine sanitiser, stabiliser is not required.
🔍 Does it suit my pool?▾
Cyanuric acid (CYA) stabiliser is only relevant for pools sanitised with chlorine or salt.
🧂Salt chlorinated▾
✓ Recommended for salt pools
Salt pools running outdoors benefit significantly from stabiliser — chlorine generated by the salt cell degrades just as quickly as added chlorine without CYA. Target 50–80 ppm for salt pools.
💧Traditional chlorine▾
✓ Primary use — outdoor chlorine pools
Standard outdoor chlorine pools are the primary use case. Target 30–50 ppm CYA to protect chlorine from UV degradation.
🪨Mineral / magnesium▾
✓ Compatible with mineral chlorine systems
Mineral pool systems using chlorine as the sanitiser benefit from CYA stabilisation in the same way as standard chlorine pools.
⚡Ionised / Nature2▾
⚠ Check system requirements
Some ionised systems have specific CYA recommendations. Check your ioniser manufacturer's guidance before adding stabiliser.
🏊Fibreglass▾
✓ Safe for fibreglass
Liquid CYA is safe for all pool surfaces including fibreglass at recommended doses.
🧱Indoor pools▾
✗ Not needed — UV is not a factor
CYA only protects against UV degradation. Indoor pools don't have UV exposure, so stabiliser provides no benefit and just accumulates.
💊 Dosage guide▾
Add directly to pool water with the pump running. Do not add to the skimmer box. Test CYA level before adding — do not exceed 100 ppm.
Initial dose (new pool / 0 ppm)
250 ml
per 50,000 L
Raises CYA by approximately 10 ppm. Test after 24 hours and repeat until target range is reached.
Top-up dose (below 30 ppm)
125–250 ml
per 50,000 L
After backwashing or partial drain, CYA levels drop. Top up to restore the 30–50 ppm target.
Salt pool target
200–400 ml
per 50,000 L
Salt pools target 50–80 ppm. Apply in stages and test between additions to avoid overshooting.
5L size advantage
Economical
for regular top-ups
The 5L is more economical for pools needing regular CYA replenishment — particularly after seasonal backwashing or partial refills.
❓ FAQ▾
What level of CYA should I aim for?▾
For outdoor chlorine pools: 30–50 ppm. For salt pools: 50–80 ppm. Below 30 ppm, chlorine degrades rapidly in sunlight. Above 100 ppm, CYA over-stabilises the chlorine, significantly reducing its effectiveness — a condition sometimes called 'chlorine lock'.
My CYA is too high. How do I reduce it?▾
Unlike most chemicals, CYA doesn't break down over time. The only way to reduce it is to dilute — partial drain and refill with fresh water. Drain approximately 30% of your pool and refill to bring levels back into range.
Is liquid CYA better than granular stabiliser?▾
Liquid CYA (like Instant Sunscreen) dissolves immediately on contact — no need to pre-dissolve in a bucket or place in a skimmer sock. Granular CYA takes 24–48 hours to fully dissolve and can damage pool surfaces if it settles. Liquid is faster, more convenient and easier to dose precisely.
Does stabiliser affect anything else in the pool?▾
CYA does not affect pH, alkalinity, calcium hardness or salt levels. It has no effect on your sanitiser type beyond moderating the UV degradation of chlorine.