Palintest DPD Oxystop Test Tablets – 250 Pack (AP017) Removes MPS Interference in Chlorine Testing

Palintest AP017 DPD Oxystop tablets neutralise potassium monopersulfate (MPS) interference during extended-range chlorine testing. They are used between the DPD XF (AP013) free chlorine reading and the DPD XT (AP033/1) total chlorine reading, preventing false-positive results caused by MPS-based shock treatment chemicals. Each pack contains 250 individually foil-sealed tablets.

When to Use Oxystop

Use Oxystop when the pool or spa has been treated with a potassium monopersulfate (MPS) shock product. MPS reacts with potassium iodide in DPD XT and gives a false elevated total chlorine reading. Adding Oxystop after the DPD XF step neutralises this interference before the DPD XT tablet is added.

Extended Chlorine Test Sequence

1. Measure free chlorine with DPD XF (AP013)
2. Add Oxystop (AP017) to neutralise MPS interference
3. Add DPD XT (AP033/1) to measure total chlorine

Key Features

• Removes MPS (potassium monopersulfate) interference from combined/total chlorine tests
• Compatible with extended-range Palintest photometers
• 250 individually foil-sealed tablets per pack
• Part number / Palintest code: AP017

Compatible Test Equipment

• Palintest Lumiso Pooltest 6 Photometer
• Palintest Lumiso Pooltest Expert Photometer Kit

Related Palintest Test Tablets

Chlorine Testing

• Palintest DPD 1 (AP011) – Free Chlorine, Photometer, 250 Pack
• Palintest DPD 3 (AP031) – Total Chlorine, Photometer, 250 Pack
• Palintest DPD XF (AP013) – Extended Free Chlorine, Photometer, 250 Pack
• Palintest DPD XT (AP033/1) – Extended Total Chlorine, Photometer, 250 Pack
• Palintest DPD Oxystop (AP017) – Removes MPS Interference, 250 Pack — this product

pH Testing

• Palintest Phenol Red (AP130) – pH, Photometer, 250 Pack
• Palintest Phenol Red (AK131) – pH, Comparator Use Only, 250 Pack

Alkalinity Testing

• Palintest Alkaphot (AP188) – Total Alkalinity, Photometer, 250 Pack
• Palintest Alkavis (250F) – Total Alkalinity, Rapid, 250 Pack

Hardness Testing

• Palintest Calcicol (AP252) – Calcium Hardness, 250 Pack
• Palintest Hardicol (AP254) – Total Hardness, Photometer, 250 Pack

Other Parameters

• Palintest Bromine (AP060) – Bromine, Photometer, 250 Pack
• Palintest Cyanuric Acid (AP087) – Stabiliser Level, Photometer, 250 Pack
• Palintest Copper (AP187) – Copper, Photometer, 250 Pack
• Palintest Chloride (AP268) – Chloride, Photometer, 250 Pack

Specifications

• Part Number: AP017
• SKU: RE-AP017
• Parameter: MPS Interference Removal (for use with DPD XF / DPD XT sequence)
• Pack Size: 250 tablets
• Format: Individually foil-sealed tablets
• Brand: Palintest
• Condition: New

Frequently Asked Questions

What is potassium monopersulfate (MPS) and why does it interfere with chlorine testing?

MPS is an active ingredient in many non-chlorine pool shock products. It reacts with potassium iodide in DPD XT reagents, producing a false positive that makes total chlorine appear higher than it actually is. Oxystop (AP017) neutralises this interference so that accurate total chlorine readings can be obtained.

Do I always need to use Oxystop when testing pool water?

No. Oxystop (AP017) is only needed when the pool has been treated with an MPS-based shock product. If only chlorine-based chemicals are used, Oxystop is not required in the test sequence.