Prepare your technical information
Water Analysis Guide
A useful RO antiscalant enquiry starts with more than a list of numbers. The water analysis should be connected to the sampling point, units, date, RO operating basis, pretreatment and the specific question being reviewed.
An incomplete report can still be submitted. ALPHX may request additional parameters or system information before a technical-commercial review can proceed.
On this page
- A number without a sampling point can be misleading
- Units and reporting basis are part of the result
- Provide the most complete representative analysis available
- “Not detected” is useful only when the reporting limit is known
- Water chemistry alone does not define the operating risk
- The water reaching the RO may differ from the source water
- State what changed or what decision is required
- Different water sources may require different supporting data
- Check the report before submission
- Submit what you have and identify what is unknown
- Attach the documents that explain the technical basis
- What to include for the stage of the enquiry
A number without a sampling point can be misleading
Before interpreting chemistry, identify exactly where and when the sample was taken.
The submission should state:
- sample date;
- sampling location;
- source-water type;
- whether the values are measured or design assumptions;
- laboratory name where available;
- relevant operating or seasonal context.
Possible sampling locations may include:
- raw source water;
- before pretreatment;
- after pretreatment;
- RO feed line;
- RO concentrate;
- another clearly identified point.
For RO antiscalant evaluation, the relevance of a result depends on whether pretreatment materially changes the chemistry that reaches the membranes.
Units and reporting basis are part of the result
Each laboratory value should retain its original:
- result;
- unit;
- reporting basis;
- test method where available;
- detection limit where relevant;
- sample date;
- laboratory source.
Examples of reporting-basis issues can include:
- alkalinity reported on different bases;
- hardness reported as CaCO₃;
- silica reported as SiO₂ or another basis;
- reactive, dissolved, total or unspecified silica;
- conductivity reported in µS/cm or mS/cm.
Converted values may be useful internally, but the original submitted value and unit should not be overwritten.
Provide the most complete representative analysis available
Not every enquiry requires every parameter, but the following groups may be relevant.
General Water Information
- temperature;
- pH;
- conductivity;
- total dissolved solids;
- turbidity;
- SDI where available;
- alkalinity;
- total hardness.
Major Cations
- calcium;
- magnesium;
- sodium;
- potassium.
Low-Level or Scale-Relevant Cations
- barium;
- strontium;
- iron;
- manganese;
- aluminium;
- ammonium where relevant.
Major Anions
- bicarbonate;
- carbonate where reported;
- chloride;
- sulfate;
- nitrate;
- nitrite;
- fluoride;
- phosphate;
- bromide or sulfide where relevant.
Silica and Related Data
Where available, identify whether the report includes:
- reactive silica;
- total silica;
- dissolved silica;
- colloidal silica;
- reporting basis.
Other Source-Specific Information
Depending on the source and process, additional information may include:
- TOC;
- COD;
- BOD;
- oil and grease;
- free chlorine;
- ORP;
- microbiological information;
- other process-related contaminants.
“Not detected” is useful only when the reporting limit is known
Some scale-related constituents can be relevant at relatively low concentrations.
For parameters such as barium and strontium, include:
- the reported value;
- the unit;
- the laboratory detection or reporting limit where available.
A missing value, a zero value and “not detected” are not necessarily equivalent.
Water chemistry alone does not define the operating risk
Include the available RO system information alongside the laboratory report.
Useful data can include:
Flow and Recovery
- feed flow;
- permeate flow;
- concentrate flow;
- design recovery;
- actual recovery;
- recycle or recirculation where applicable.
Configuration
- number of passes;
- number of stages;
- array;
- pressure vessels;
- elements per vessel.
Membrane Information
- manufacturer;
- model;
- membrane age;
- replacement history;
- first-pass / second-pass allocation where relevant;
- known compatibility or OEM restrictions.
Operating Conditions
- feed pressure;
- interstage pressure where available;
- concentrate pressure;
- differential pressure;
- permeate pressure;
- operating hours;
- start/stop frequency;
- temperature range;
- feed pH;
- normalised permeate flow where available;
- normalised salt rejection or salt passage where available.
The water reaching the RO may differ from the source water
Describe the pretreatment train and chemical programme as clearly as possible.
Possible pretreatment information includes:
- screening;
- clarification;
- coagulation / flocculation;
- media filtration;
- activated carbon;
- softening;
- iron / manganese removal;
- UF or MF;
- cartridge filtration;
- dechlorination;
- acid dosing;
- other chemical additions.
Current chemical information may include:
- antiscalant brand and grade;
- current dosing rate;
- product dilution;
- day-tank concentration;
- dosing-pump make/model;
- pump calibration;
- injection point;
- acid type and dose where applicable;
- SMBS or other reducing-agent dose;
- coagulant / polymer dose;
- biocide or CIP chemicals where relevant.
State what changed or what decision is required
A technically useful submission should explain the reason for review.
Examples supported by the project workflow include:
- selecting an antiscalant;
- reviewing an existing programme;
- replacing a current product;
- changing recovery;
- changing source water;
- investigating visible scale;
- investigating reduced permeate flow;
- reviewing increased pressure or differential pressure;
- reviewing increased salt passage;
- frequent CIP;
- suspected silica, sulfate or carbonate scale;
- mixed or uncertain fouling;
- evaluating a new project;
- preparing a quotation request.
Different water sources may require different supporting data
Seawater
Additional context may include:
- salinity;
- temperature range;
- boron and bromide where relevant;
- SWRO membrane model;
- pass configuration;
- chlorination / dechlorination;
- biofouling history.
Well or Groundwater
Additional context may include:
- iron;
- manganese;
- barium;
- strontium;
- silica;
- hydrogen sulfide where relevant;
- seasonal variation;
- iron-removal details.
Treated Wastewater or Variable Reuse Water
Additional context may include:
- TOC;
- COD;
- BOD;
- ammonium;
- phosphate;
- oil and grease;
- SDI / MFI;
- microbiology;
- coagulant residual;
- UF performance;
- biofouling history.
Check the report before submission
A stronger submission avoids obvious inconsistencies.
Review:
Range and Unit Checks
- pH should be reported on the correct scale;
- recovery should be expressed consistently;
- flows and concentrations should not be negative;
- units should match the stated parameter.
Flow Balance
Where data are available, feed flow should approximately reconcile with permeate plus concentrate flow, allowing for declared recycle or side streams.
Recovery Check
Submitted recovery should be consistent with the available feed and permeate flows.
Hardness Consistency
Where detailed calcium and magnesium data are available, total hardness should not conflict materially without explanation.
Ion Balance
Where sufficient ionic data exist, charge balance can help identify incomplete or inconsistent analysis.
TDS and Conductivity
Major inconsistency between reported TDS and conductivity should be reviewed, without assuming one universal conversion factor.
Report Age and Representativeness
Older data may be less useful when:
- source water varies seasonally;
- operating conditions changed;
- blending changed;
- pretreatment changed.
Submit what you have and identify what is unknown
Do not invent missing values.
A submission may still begin with:
- a partial laboratory report;
- an older report clearly labelled as such;
- available system data;
- product documents;
- operating logs;
- photographs;
- a concise explanation of what is missing.
Additional information may be required when, for example:
- there is no water analysis;
- sample location is unknown;
- units or reporting bases are missing;
- only raw-water data are available but pretreatment changes chemistry;
- recovery or membrane information is missing;
- relevant scale-forming ions are not reported;
- flow data are inconsistent;
- source water is highly variable;
- non-scaling fouling may be involved;
- the current dosing system has not been verified.
Attach the documents that explain the technical basis
Useful files may include:
- recent water-analysis report;
- RO system design or membrane projection;
- operating-data trends;
- current antiscalant TDS/SDS;
- dosing information;
- CIP history or reports;
- deposit photographs;
- membrane photographs;
- laboratory or deposit-analysis reports;
- current product specification.
What to include for the stage of the enquiry
Include Water and System Information When
- product selection is still open;
- water or operating conditions need review;
- the current programme is being questioned;
- the source water changed;
- a technical problem is being investigated;
- the technical basis is incomplete.
Include Purchasing Information When
- the product or specification is already defined;
- quantity is known;
- destination is known;
- required documents are listed;
- purchasing timing is clear.
Prepare a clearer technical submission
Send the report together with the system context
Submit the available water analysis and RO system information. ALPHX will review the application and establish the appropriate basis for product evaluation, dosing review and commercial coordination.