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  • Significantly safer on metals than competing hydrochloric acid based descalers
  • Safe on carbon steel, aluminum, stainless steel and copper
  • Readily biodegradable
  • Odorless - making it safer to handle
  • Low foaming chemistry for added safety


Eco-Lyme is a new odorless chemistry for the HVAC/R market that provides a unique blend of performance and safety to the environment and user. The product is specially formulated to achieve descaling behavior of competing hydrochloric acid based descalers. However, the active ingredient is substantially safer on equipment metals. Eco-Lyme is ideal for stainless steel construction - eliminates the issue of localized corrosion/pitting caused by repeated use of hydrochloric acid.

Eco-Lyme is readily biodegradable per OECD 301A, a recognized international method for determining biodegradability for applicable chemistry. Eco-Lyme uniquely provides top-tier performance with a validated eco-profile when a ‘green’ descaler is sought.

Eco-Lyme is formulated to remove scale, rust and other water deposits from cooling towers, evaporative condensers, hot water boilers, processing equipment and more. Scale affects the performance, efficiency, and potentially design life of the equipment. For cooling tower applications, scale restricts water flow and quickly reduces heat transfer capability of the heat exchanger resulting in elevated high side pressure of the refrigerant system. Excessive high side pressure causes the compressor to draw extra current, which leads to increase power cost over time and may lead to a shorten life. In addition, the scale in the heat exchanger dramatically affects the capability of the equipment to operate at a designed condition. Nu-Calgon offers a family of products for water treatment to prevent scale build-up in cooling towers and evaporative condensers. For other situations when scale must be addressed, Eco-Lyme is the ‘green’ solution.

Eco-Lyme is ideal for heat exchanger descaling of hot water boilers due to its desired performance and is safer on ferrous and aluminum materials used in heat exchanger construction (see table on back page). Eco-Lyme is advantageous for descaling processing equipment (tanks and/or lines) of a stainless steel and/or aluminum construction. Eco-Lyme provides superior descaling capability, while having similar metal compatibility of phosphoric acid traditionally used in these applications.

Packaging Size Part Number Additional Info
1 Gallon Bottle 4167-08
5 Gallon Bottle 4167-05
55 Gallon Drum 4167-01


This product must be used in accordance to the following directions by HVACR professionals only.

Descaling Instructions – Cooling Towers

Eco-Lyme will safely descale copper, stainless steel, steel, aluminum, iron, brass, wood, rubber and plastic equipment. Wear goggles and protective gear.

  1. Shut-off bleed and makeup water to cooling tower.
  2. Drain water from sump. Scrap or hose down loose scale from slats or coil. Flush out sump to remove loose scale and sludge. This step will reduce the amount of Eco-Lyme needed to descale the cooling tower.
  3. Fill system with water.
  4. Add an initial Eco-Lyme dosage to the water circuit following the system tonnage schedule shown on product bulletin 3-43.
  5. As the descaling solution circulates, monitor solution activity in the cooling tower sump. Eco-Lyme is a strong chemistry that will descale quickly. It’s normal to see some bubbling from carbon dioxide gas release as Eco-Lyme descales the equipment. This bubbling or sputtering will fade as the Eco-Lyme is consumed.
  6. It is recommended to test the working strength of the Eco-Lyme in 15-20 minute intervals to establish if the descaler is at an active (working) strength.
  7. This can easy be done with the supplied pH strips that accompany each package size of Eco-Lyme. Simply place a pH strip in the descaler solution. If the pH strip turns red, then the solution is still at an active strength. If the pH strip remains yellow/orange, the initial dosage of Eco-Lyme has been consumed and more is required. Add more Eco-Lyme and repeat monitoring the pH of the solution with pH strips every 15-20 minutes.
  8. The system is free of scale when the solution retains its active strength (red color on pH paper) for a minimum of 30 minutes. Typically, systems can be descaled within four hours. Some applications may be heavily scaled and may require some additional time. Never leave Eco-Lyme in the system any longer than necessary and never longer than six hours.
  9. Drain and flush out the sump again, removing all the Eco-Lyme solution along with sediment that may have been loosened. Discard biodegradable Eco-Lyme solution following local regulations.
  10. Fill the system with fresh water and open bleed.
  11. Consider setting the cooling tower up with a Nu-Calgon Water Treatment Program in the prevention of unwanted scale. Contact Nu-Calgon for further details.

*Initial dosage guidelines shown in table are nominal starting points in the descaling process developed from historical experience. A good rule of thumb of a starting dosage is one gallon of Eco-Lyme per 2.5 tons of cooling capacity. For adverse scale applications, more Eco-Lyme will be required. The advantage of nominal lower dosage amount shown in table is that Eco-Lyme is only added after further monitoring that has established more is needed. This minimizes the amount of Eco-Lyme that is needed per job or the amount that will need to be neutralized before disposal.

Remember, a more dilute solution of Eco-Lyme will dissolve the same amount of scale as a more concentrated Eco-Lyme solution. However, the rate will be slower. The dilution recommendations above are intended to provide guidelines on desired descaling rates. Adjust according if desired. Warning: Eco-Lyme may remove zinc from galvanized metal -consider Season Treat in this circumstance.

Click on "Product Information" and download product bulletin 3-43 for more details and to get instructions for Shell and Tube Condensers.

Product Information:

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Download the product bulletin and other relevant literature here.


Download a low resolution file of the product label here.

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RTK Information

2611 Schuetz Rd. St. Louis, MO 63043
  • Telephone: 800.554.5499
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  • Hours: Mon–Fri: 8:00am - 5:00pm (Central Time)

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