Frequently asked questions

There is no fixed calendar interval. Clean when normalized performance shows a clear change from the commissioning baseline: a rising differential pressure, falling normalized permeate flow or rising salt passage. Cleaning earlier, while the deposit is still thin, recovers performance more fully than waiting until the loss is severe.

A rising differential pressure means the feed channels between membrane sheets are being blocked. The usual causes are particulates and colloids, biological growth, or scale from sparingly soluble salts. Where in the train the rise starts, and how fast it moves, helps separate these causes before choosing a cleaner.

An antiscalant keeps sparingly soluble salts, such as carbonates and sulfates, in solution as the feed water is concentrated along the membrane train. It delays crystal growth and deposition on the membrane surface, so recovery can be run without scale forming in the concentrate stream.

Start from a current feed water analysis and the planned recovery, then set the treatment rate from the analysis and operating conditions rather than from habit. Confirm the choice by watching differential pressure and salt passage, and review it whenever the feed source, recovery or temperature changes.

Mineral scale is normally removed with an acidic cleaner, while biological and organic deposits respond to an alkaline cleaner. The right order depends on what the deposit is, so identify the foulant from the performance trend and a cleaning analysis first, and rinse thoroughly between the two steps.

Microorganisms in the feed attach to the membrane and spacer surfaces, multiply on the nutrients present and build a slimy biofilm that raises differential pressure and lowers flow. It is usually worse after warm weather, a weak pretreatment barrier or a period of idle stagnation.

Baseline readings of pressures, flows, conductivity and temperature taken at start-up show what clean membranes do on the actual feed water. Later trends are judged against them, so fouling and scaling can be identified early instead of being mistaken for normal seasonal change.

RO maintenance covers routine performance logging and normalization, cartridge filter and pretreatment checks, chemical feed checks, membrane cleaning when the trend calls for it and a review of operating data.

Normalize permeate flow, differential pressure and salt passage for feed temperature, pressure and recovery, then compare them with the start-up baseline. Raw readings move with the seasons and load. A steady drift in the normalized values, not a swing in the raw ones, points to fouling or scaling.

Pretreatment removes or controls what would otherwise foul the membranes: suspended solids, oxidants that attack the polymer, dissolved organics and microorganisms. A weak pretreatment stage shows up downstream as faster fouling, more frequent cleaning and a shorter membrane life.

Flush the system with suitable quality water, then keep the membranes wet and preserved with a suitable disinfectant solution so that biological growth cannot establish. Membranes must never be allowed to dry out. Follow the membrane supplier instructions for the preservation solution and for restart.

Corrosion follows from dissolved oxygen, low or aggressive pH, high chloride and sulfate content, galvanic contact between different metals, and deposits or biofilm that create under-deposit attack. Concentrating the water by evaporation makes each of these worse unless blowdown and inhibitor treatment keep the chemistry in balance.

Evaporation concentrates dissolved hardness and alkalinity in the recirculating water. Where solubility is exceeded, especially on warm heat-transfer surfaces, calcium carbonate and related salts crystallize and deposit. High cycles of concentration, high pH and high temperature all raise the scaling tendency.

Conductivity is a quick indicator of how concentrated the circulating water has become, so it is the usual control signal for blowdown. Too high and scale and corrosion risk rise; too low and water and chemicals are wasted. It supports, but does not replace, a full water analysis.

Control combines a clean, well-drained system, removal of deposits that shelter organisms, and a biocide programme monitored by microbiological testing. Isothiazolinone-based and DBNPA-based biocides are both used in cooling systems, and alternating them is a common way to keep microorganisms from adapting.

Scale appears as hard, pale, adherent crust on warm surfaces and fill, and shows up as falling heat transfer. Corrosion appears as red-brown or black tuberculation, pitting, metal loss and iron in the water. Inspection of exchanger surfaces plus water and coupon results settle which one dominates.

Monitor pH, conductivity, the inhibitor residual such as zinc where a zinc-based product is used, corrosion indicators from coupons or probes, and microbiological counts. Together they show whether blowdown, inhibitor and biocide are keeping scale, corrosion and growth under control.

Even a sealed loop corrodes when oxygen enters through make-up water, leaks or open expansion tanks, when the inhibitor residual falls, or when mixed metals and deposits set up galvanic and under-deposit attack. Water that is not monitored drifts out of its protective range unnoticed.

It is a corrosion inhibitor based on sodium nitrite that forms a thin protective film on steel surfaces in closed chilled-water circuits. Its protection depends on keeping the nitrite residual within the range stated for the product, which is why regular testing of the loop water is part of the programme.

A closed loop is never perfectly closed: make-up water, small leaks and maintenance openings let in oxygen, minerals and microorganisms. Untreated, the loop corrodes, sheds iron that fouls heat exchangers and may support microbial growth, all of which reduce cooling efficiency and shorten equipment life.

Test the loop water for the inhibitor residual, nitrite in the case of a nitrite product, together with pH, conductivity and iron, and compare corrosion coupon results over time. A falling residual or rising iron signals a leak, make-up dilution or active corrosion that needs a response.

Yes. Low-flow branches, dead legs and warm sections let bacteria establish biofilm even in a closed loop, and some bacteria accelerate corrosion under the film. Good circulation, clean make-up water and periodic microbiological testing, with biocide treatment where results call for it, keep the loop healthy.

Every addition of make-up water dilutes the inhibitor and brings in fresh oxygen, hardness and chlorides. Frequent or unexplained make-up is therefore a warning of leakage, and the inhibitor residual should be re-tested and restored after any significant top-up or draining.

Hardness salts and silica carried in with feedwater lose solubility as the water heats and concentrates, and bake onto hot heat-transfer surfaces. Poor feedwater softening, high concentration without enough blowdown, and metal oxides from corroding condensate lines all add to deposits that insulate the tubes and cause overheating.

Dissolved oxygen in feedwater attacks steel quickly when the water is hot, causing pitting in the feedwater heater, economizer and boiler. Incomplete mechanical deaeration, air leaks into the condensate return and a missing or underfed oxygen scavenger leave the oxygen free to react with the metal.

Both remove dissolved oxygen from boiler feedwater. Sulfite-based scavengers react quickly but add dissolved solids and are usually limited to lower-pressure boilers. DEHA-based scavengers add no dissolved solids and also help passivate metal surfaces, so the choice follows boiler pressure, water quality and feedwater system design.

Carbon dioxide from decomposing alkalinity dissolves in condensate to form carbonic acid, which lowers pH and eats away the pipe wall, often as grooving. Oxygen entering the return system adds further attack. A neutralizing amine raises condensate pH so the acid is neutralized along the line.

Steel is protected by a stable oxide film only in mildly alkaline water. If feedwater or boiler water pH is too low, the film dissolves and corrosion accelerates; if it is too high, caustic attack and carryover become risks. A pH booster adjusts the water into the protective range.

Conductivity tracks the dissolved solids that build up as steam leaves and feedwater replaces it. It guides blowdown: too high invites scale, foaming and carryover into the steam, too low wastes heat and treated water. It is read together with pH and the treatment residuals.

Yes. Our technical datasheets state the category, application, function, product type and packaging. Approved datasheets are published on the product page, and our technical team can send the datasheet that matches your system on request, including for products whose sheet is still being prepared.

Every product datasheet lists the same pack sizes in its packaging section, from smaller packs up to an intermediate bulk container (IBC), and the product page shows them under Packaging. Tell our technical team the size you need when you request a quote.

Product samples are requested from our technical team, as our datasheets state. Use the request form and name the product or the problem you want to test, with your application and water details, so that the sample suits your system.

The rate is set from the water analysis and the operating conditions of the system, then confirmed by monitoring, not read from a fixed table. Pressure, temperature, cycles of concentration and make-up water quality all change what is needed, so the rate is reviewed whenever those conditions change.

Send your operating data and a recent water analysis to our technical team: the system type, feed or make-up water source, key operating conditions, the problem you see and any past treatment. With that, the team can match a product category and monitoring plan to your system.

Match the category to the system and the problem. RO plants use antiscalants and membrane cleaners. Open cooling towers use scale and corrosion inhibitors with biocides. Closed chilled-water loops use a closed-loop inhibitor. Boilers use oxygen scavengers, pH boosters, scale inhibitors and, for condensate, neutralizing amines.