Guide to Lowering Cyanuric Acid (CYA) with CYALocker

This guide shows how to lower CYA step by step with CYALocker^®.
No draining. No refilling. No starting over.

How to Use Explore CYALocker in Depth

Common reduction: ~100 ppm (150 ppm down to 50 ppm)

Severe case tested: 492 ppm down to 56 ppm, no draining

Backed by lab studies and multi-state field trials

ZERO GALLONS DRAINED

One pouch treats 10,000 gallons, right in the skimmer basket.

INSTRUCTIONS

How to Use CYALocker

Dosing Quick Reference:

STARTING CYA (PPM)	POUCHES PER 10,000 GAL	AVERAGE REDUCTION PER TREATMENT
Under 60	1	~30 ppm
60–100	1	30–50 ppm
100–150	1	50–80 ppm
150–200	1	80–100 ppm
200+	1	100–150 ppm

NOTE: Results will vary depending on water chemistry, temperature, sunlight, and filtration. Use with Beautec may affect CYALocker performance by interfering with the biodegradation process.

If CYA is above 200 ppm, additional CYALocker pouches may be required.

Step 0 - Before You Start

✓
No algae. Kill any algae first.
✓
Chlorine (Cl) below 5 ppm. High chlorine prevents the treatment from working. Chlorine level must be below 5 ppm before treatment begins.
✓
Water above 60°F. Recommended for best performance. Colder water still works, just slower, since it carries less energy.
✓
Clean filter. A gunked-up filter slows everything down. Start with a clean filter and an empty skimmer basket. Good water flow is what makes the treatment work.
✓
Phosphates in check. If phosphates are high, treat them first with PhosLocker, or run it alongside. CYALocker w Phos Control handles up to 1,000 ppb on its own; above that, use standard PhosLocker too.

01

Run the checklist. Work through the Before You Start list, so the water is ready.

02

Drop in the pouch. Once the checklist is complete, place one pouch per 10,000 gallons in your skimmer basket or inline canister, anywhere water flows through it.

03

Around day 14, add non-chlorine shock (MPS). One dose. Do NOT superchlorinate during treatment.

04

Test weekly and let it work. When you're done, the spent pouch can be opened and added to garden soil. Your plants will thank you.

WHAT TO EXPECT

The Typical CYALocker Treatment Curve

Here's what to expect from your test readings during treatment.

a

Initial CYA level (DAY 0)

Your baseline reading before treatment begins.
b

Temporary CYA increase (DAYS 1–7)

Readings may rise early on. This artificial peak is a testing anomaly, a false positive rather than a real increase in CYA.
c

Leveling-out phase (DAYS 7–14)

Readings hold fairly stable after the peak, just before the decline begins.
d

Steep reduction phase (DAYS 14–28)

Add one dose of non-chlorine shock (MPS) around day 14, marked by the dotted line. False-positive readings drop after it, can drop 50 to 100 ppm in a week.
e

Continued reduction (DAYS 30–60)

CYA nears the target range, then levels off. Ongoing tablet use may hold it steady.

Measured CYA (ppm) over 60 days. The shaded band marks the first two weeks, where every line shows the same early bump from test-kit interference.

Note: CYALocker results may vary when used with Beautec due to interference with the biodegradation process.

Days of treatment

Starting 200 ppm

Starting 150 ppm

Starting 100 ppm

Starting 80 ppm

Important: CYA readings often test higher in the first couple of weeks. As the molecule breaks apart, the fragments react with the melamine reagent in test kits and cloud the sample. Readings typically drop after weeks 2 to 3, especially after the non-chlorine shock step. Results vary with water chemistry, temperature, sunlight, and filtration. Above 200 ppm CYA, additional pouches may be required.

THE PROCESS

The CYALocker Technology

CYALocker works with your pool's normal filtration system to reduce cyanuric acid (CYA) through a controlled biodegradation process. No mixing, no measuring, no dosing schedule. Here's the whole journey:

1

Water flows through the pouch

As pool water circulates through your filter system, it passes through the CYALocker media pouch.

2

CYA is captured

The media specifically targets and bonds with cyanuric acid molecules as water flows through.

3

Controlled biodegradation

Once captured, the CYA molecules are broken down inside the pouch, so they're actually gone, not sitting in a filter waiting to leach back.

4

CYA drops over time

As the process continues, CYA levels in the water gradually decrease.

5

Cleaner, balanced pool water

Lower CYA restores your chlorine's efficiency and overall water balance.

That's why we call it subtractive technology. Liquids and clarifiers change how your water looks. CYALocker changes what's in it.

One thing it needs from you: water flow. The pouch only works on water that passes through it, so it goes in your skimmer basket or an inline canister, right in the current.

A Deeper Look for Pool Pros

The full chemistry, performance data, and what it means for your service routes.

Mechanism

Cyanuric acid (CYA) hydrolyzes into biuret as the first degradation phase. The terminal amide groups on the biuret structure bond and hold free chlorine, which is why chlorine demand rises mid-treatment and why the MPS oxidation step at around day 14 matters: it releases bound chlorine and oxidizes biuret onward into amines that don't permanently hold chlorine. Structurally, biuret behaves much like urea, where attached chlorine oxidizes off readily. This is also the source of the temporary false-high CYA readings: intermediate breakdown compounds react with the melamine reagent in turbidity-based test kits.

Chlorine Control

Free Chlorine (FC) above 5 ppm halts the biodegradation process, and it won't restart on its own. If a service account needs superchlorination, do it before treatment and wait (or neutralize) until FC is back under 5 ppm. Conversely, superchlorination is your off-switch if you ever need to stop biodegradation deliberately.

Route Economics

Every drain-and-refill you avoid is a truck roll, a water bill, and a liability conversation you don't have. CYALocker installs in the skimmer during a normal service visit.

Performance Conditions

Optimal above 60°F (slower, not stopped, below). Keep phosphates under 1,000 ppb; pre-treat or co-treat with PhosLocker. Clear algae and heavy organic load first, since the catalyst capacity you want on CYA gets consumed by other organics.

Field Performance & Lab Results

In service-route field trials, treated pools dropped from roughly 490 ppm CYA to under 90 ppm over a season while tabs continued adding stabilizer. One 13,000 L residential trial removed 180 ppm (244 down to 64 ppm, a 73.8% reduction). Lab comparatives at matched and even 5x to 10x competitor doses showed materially faster and deeper reduction, with single-dose removal efficiencies of 87 to 97% in blend testing.

FIELD RESULTS · SERVICE-ROUTE TRIAL

Tracked Weekly. Tested Openly. Zero Draining.

These are just 3 of the 4,000+ pools treated with CYAlocker. All three are 25,000-gallon pools, each with a different surface, a different algae history, and a different treatment scenario. The cases change; the way CYAlocker works doesn't. Across the board, an average of –93% CYA removed without draining a single gallon. Here's every CYA test reading from the trial:

Pool A

492 → 56 ppm

–89% CYA

The stubborn one. A 25,000-gal pebble dive pool inherited as a green swamp with a two-year mustard algae history. The hard-case scenario: heavy tab dependence and CYA pushing 500. By the end of the trial, the pool was clear, off tabs entirely, and not a drop was drained.

Pool B

486 → 54 ppm

–89% CYA

The combo treatment. A 25,000-gal older plaster pool with mustard algae on the walls at takeover. This one tested how CYAlocker plays with other chemistry: PhosLocker ran alongside to keep phosphates in range. Both treatments were dosed in the same skimmer visit, with no conflict and the same steady drop.

Pool C

298 → 0 ppm

–100% CYA

The full reset. A 25,000-gal plaster pool with algae and heavy debris at takeover. Instead of just lowering CYA, this pool was taken all the way to zero, then deliberately re-stabilized to an ideal 20–30 ppm with occasional tabs. Proof you control exactly where the number lands.

ANSWERS

Frequently Asked Questions

Why is the Cyanuric Acid (CYA) in my pool so high?

Common chlorine products like trichlor tablets and dichlor contain CYA, also known as stabilizer or conditioner. At the right level, CYA protects chlorine from sunlight and helps it last longer. The challenge: every dose of stabilized chlorine adds more CYA, and while chlorine gets used up, CYA doesn't leave the water nearly as quickly. It slowly accumulates until levels are too high. As CYA rises, you need more and more free chlorine to keep the pool properly sanitized. The water gets harder to keep clear, even when a test still shows chlorine present.

Why did my cyanuric acid (CYA) go UP after starting treatment?

The early rise (typically 10 to 30 ppm in the first two weeks) is a testing quirk, not real CYA. As the molecule breaks apart, the fragments react with the reagent in standard test kits and cloud the sample, which reads as a higher number. Readings typically drop after weeks 2 to 3, especially after the non-chlorine shock step.

How long does it take to lower cyanuric acid (CYA) in a pool?

About 30 to 60 days for a full treatment, with a typical result of 150 ppm down to 50 ppm. Warm water, a clean filter, and good circulation speed things up. Cold water slows it down but doesn't stop it.

Can I keep swimming during treatment?

Yes. The pool stays open the entire time. The media stays sealed in its pouch, and you keep your normal chlorine routine.

Do I need to stop using chlorine tablets?

Not during treatment. Field trials showed CYA dropping even while tabs kept adding stabilizer. Long term, though, tabs are what caused the problem, so many owners switch to liquid chlorine afterward to keep CYA low for good.

What if my pool has algae or high phosphates?

Handle those first. Shock to kill the algae, wait for Free Chlorine (FC) to drop back below 5 ppm, and bring phosphates down with PhosLocker (or run it alongside). Then start CYALocker.

Stop Draining. Start Subtracting.

Your water is fine. Your stabilizer isn’t. Fix the actual problem without wasting 10,000 gallons to do it.

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One pouch treats 10,000 gallons

Spent media is garden-safe

Questions? Contact RecH2O, LLC

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