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Closed Systems Water Treatment

Hydrolink Technologies Limited provides a range of high quality water treatment chemicals for all types of closed circuit heating, cooling and chilled water systems.

Closed circuit or closed loop water systems are a closedsysconvenient way of heating or cooling building services applications and industrial and commercial processes. As the name “closed loop” suggests the intention is generally to retain the same water in the system for an indefinite period which means that without effective water treatment corrosion products and foulants can build up impairing flow and heat transfer and control valves can become blocked and inoperative.

Heating systems can become scaled up; chilled water systems can become corroded, choked with pseudomonas slime-forming bacteria. A poorly treated closed circuit water system will be wasting your money long before it starts to leak.

To overcome these many potential problems we offer a comprehensive range of cost effective inhibitors and biocides which are designed specifically for closed systems. If your system is already suffering because of inadequate water treatment don’t despair because we can provide products and services which will restore flow and heat transfer to even heavily fouled systems.


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Closed circuit inhibitors are matched to the system metallurgy and operating temperature. Most of the inhibitors are designed to protect a range of different metals but particular care needs to be taken if a system contains aluminium.

Hydro 4040 D is a DEHA based oxygen scavenger which is used in the treatment of HTHW systems.

Hydro 4040S is a sulphite based oxygen scavenger which is used in the treatment of LTHW Systems.

Hydro 2555 is an industry standard nitrite based closed circuit corrosion inhibitor for LTHW and chilled water systems. Not suitable for systems containing aluminium.

Hydro tan 4T is a tannin based oxygen scavenger and heating system corrosion inhibitor which is used in the treatment of larger, predominantly steel, systems which can be used across the temperature range from chilled water to HTHW systems.


If untreated closed loop systems can become a breeding ground for a range of troublesome microbes such as pseudomonas, nitrifying and sulphate reducing bacteria. They can cause fouling, destroy closed loop inhibitors and cause MIC (microbially induced corrosion).

A chilled water biocide is essential to prevent slime growth and we would always recommend a closed circuit biocide is incorporated in any system operating below 80 °C.

Hydro 3422 is a broad spectrum closed loop biocide which effectively controls all the commonly encountered bacteria in closed water systems.

Glycol Antifreezes

Hydro freeze 99 is inhibited mono ethylene glycol antifreeze designed specifically for use in chilled water systems in industrial and building services HVAC applications.

Hydro pan 80 is food-grade inhibited propylene glycol antifreezes that can also be used as bacteriastats to safely control microbial growth in food production applications.


We offer a range of heating system cleaning chemicals and closed system chemicals for pre-commission cleaning, descaling and renovation cleaning of all types of closed circuit water systems.


Descalers and Chemical Cleaners

Hydrolink Technologies Limited supplies a range of high quality, descaling chemicals and water system cleaning chemicals for both local and export customers. We have many years of hands-on experience disinfecting and cleaning all kinds of industrial and commercial water systems so if you don’t fancy doing it yourself we can do it for you.

Our industrial water system descaling and acid cleaning products are easy to use and come with full technical support, take a look at what we offer  and discuss with us on how we can assist you today.


Pre-commission Cleaning Chemicals & Closed System Renovation Cleaners

Hydro clean 100 is an alkaline pre-commission chemical cleaner which is used to clean new closed system heating and cooling systems to remove corrosion products and other contaminants prior to the system being inhibited.  It is also a high strength non-acidic chelant cleaner which can be used both for pre-commission cleaning and renovation / restoration cleaning of closed systems. It is extremely effective at dissolving rust and other corrosion products and can restore flow and heat transfer to severely fouled systems. It is also a special surfactant for removing oil and grease.


Descaling Chemicals and Acid Cleaning Chemicals

Descaler HF is an inhibited liquid acid cleaning product based on hydrochloric acid which is ideal for boiler scale removal and descaling heat exchangers which are choked with lime-scale and other deposits.

Descaling Powder is a sulphamic acid based cleaner which is milder in its action than Descaler HF and is ideal for cleaning sensitive equipment like stainless steel heat exchangers and cooling towers.

Neutralising Powder can be used to neutralize the acid cleaning effluent before discharging it to sewer or foul drain.