ATMP vs HEDP: Which Scale Inhibitor Should You Choose?
ATMP and HEDP are both organophosphonic-acid scale and corrosion inhibitors; the key difference is that HEDP tolerates higher temperatures and chlorine, while ATMP gives strong calcium-carbonate threshold inhibition at low cost.
Quick comparison
- ATMP — excellent CaCO₃ threshold inhibition, good chelation, economical; best in circulating cooling water.
- HEDP — better thermal and chlorine stability, strong against calcium scale; suited to higher-temperature and oxidizing conditions, low-pressure boilers.
Which to choose
Choose ATMP for general cooling-water scale control and chelation; choose HEDP where temperatures are higher or an oxidizing biocide (chlorine) is dosed. They are often blended with PBTC for chlorine-rich systems.
ATMP vs HEDP at a glance
| Property | ATMP | HEDP |
|---|---|---|
| Type | Amino-phosphonate | Hydroxy-phosphonate |
| CaCO₃ inhibition | Excellent | Very good |
| Temperature stability | Good | Better |
| Chlorine / oxidant tolerance | Moderate | Higher |
| Best for | Circulating cooling water | High-temp / chlorinated, LP boilers |
Watch
Frequently asked questions
Is HEDP better than ATMP?
Not universally — HEDP tolerates higher temperature and chlorine, ATMP gives strong, economical CaCO₃ inhibition. The right choice depends on the system.
Can ATMP and HEDP be used together?
Yes — phosphonates are often blended, and combined with polymers and PBTC, for broad-spectrum scale and corrosion control.
About the manufacturer
VCYCLETECH is a China-based manufacturer of water treatment chemicals — antiscalants, scale & corrosion inhibitors, coagulants, flocculants, biocides, dispersants and paper chemicals — ISO 9001 / 14001 / 45001 certified, with a COA on every batch and OEM/ODM service. See our quality & certifications.
Related: What is an antiscalant · ATMP · HEDP · Cooling water