Astralpool / Rolachem pH 7.5 Calibration Solution - 100ml, 200ml
Astralpool / Rolachem pH 7.5 Calibration Solution - 100ml, 200ml - is temporarily out of stock and will ship as soon as it's available.
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Astralpool / Rolachem pH 7.5 Calibration Solution - 100ml, 200ml
Astralpool / Rolachem pH 7.5 Calibration Solution - 100ml, 200ml - is temporarily out of stock and will ship as soon as it's available.
AstralPool / RolaChem pH 7.5 Calibration Solution – 100mL & 200mL
Genuine AstralPool / RolaChem pH 7.5 calibration solution for checking and calibrating pH probes used with automatic pool and spa chemical dosing systems.
Supplied as a genuine AstralPool / RolaChem part, but the solution itself is a standard pH 7.5 reference buffer and is not brand-specific. It can be used to calibrate pH probes from other manufacturers wherever the calibration procedure specifies a pH 7.5 reference value.
pH probes can gradually drift from their correct reading due to normal use, contamination and ageing. Calibration against a known pH 7.5 reference solution allows the controller to compensate for this variation and maintain more accurate pH monitoring and chemical dosing.
Available Sizes
- 100mL – Fluidra / AstralPool Part No. 600116
- 200mL – Fluidra / AstralPool Part No. 600113
Suitable For
- AstralPool RolaChem pH probes and controllers
- RolaChem RC9 / RC 9 combined ORP and pH controllers
- RolaChem RP9 / RP 9 pH controllers
- Other brands of pH probe, controller, dosing system or handheld meter calibrated against a pH 7.5 reference solution
Use With Other Brands of pH Probe
pH calibration solution is a chemical reference standard rather than a branded consumable. What matters is the reference value the equipment is calibrated against, not the badge on the bottle.
If the manufacturer of your pH probe, controller or meter specifies calibration against a pH 7.5 solution, this product can be used. That makes it a semi-universal pH 7.5 reference suitable for a range of pool, spa and water treatment pH sensing equipment, not only AstralPool and RolaChem.
Please check the value your equipment uses. pH 7.5 is less common than pH 7.0, which is the reference value specified by many pH probes and meters. Some equipment also uses a two-point procedure requiring a second solution such as pH 4.0. Confirm the reference value stated in your calibration procedure before ordering.
Why pH Probe Calibration Matters
An incorrectly calibrated pH probe can cause the controller to display an inaccurate pH value. Because automatic dosing equipment relies on the probe reading when controlling acid or pH correction, an inaccurate probe can result in incorrect chemical dosing.
Regular calibration helps confirm that the displayed pH value accurately reflects the condition being measured and can also assist when diagnosing an ageing or contaminated pH probe.
RolaChem RC9 Calibration
For RolaChem RC9 systems, AstralPool's calibration procedure involves placing the controller into Manual Off, selecting MAINT > CAL > pH and calibrating the pH probe against the known reference solution.
When using calibration solution rather than pool water as the reference, the controller's Filter Pump calibration option should be set to NO. The measured value can then be adjusted to match the reference solution value of pH 7.5.
For other brands, follow the calibration procedure published by that equipment's manufacturer.
Product Details
- Reference value: pH 7.5
- Type: pH buffer / probe calibration solution
- 100mL Part Number: 600116
- 200mL Part Number: 600113
- Brand: AstralPool / RolaChem / Fluidra
- Application: pH probe and sensor calibration on pool, spa and water treatment equipment
Important: This is pH calibration solution. It is not ORP calibration solution and should not be used to calibrate an ORP/chlorine probe. It is not a pH increaser or reducer and should not be added to the pool or spa.
To the layperson, plumbing sizes and their names can be confusing due to the nominal sizes and naming conventions used.
This is not something we made up. Plumbers and manufacturers have used nominal (meaning ‘by name only’) sizing for decades.
Simply put, in plumbing, named sizes are often not the actual measurements of the pipe, fitting, or part. A PVC pipe called “50mm” or “2"” does not measure 50 mm anywhere. Instead, it follows nominal sizing, an internationally-standardised naming system.
Almost all fittings we use in the pool & spa industry use “pressure PVC” pipe & fittings. Do not confuse with “DWV” or other pipe & fittings and their names and sizes.
Use the Outside Diameter (OD) to check your pipe against fittings. Below is a quick reference for common spa & pool pipe sizes:
| Imperial Name | Metric Name | Pipe Diameter (OD) |
|---|---|---|
| 1/2" | 15mm | ~21.2–21.5 mm |
| 3/4" | 20mm | ~26.6–26.9 mm |
| 1" | 25 mm | ~33.4–33.7 mm |
| 1.5" | 40 mm | ~48.1–48.4 mm |
| 2" | 50 mm | ~60.2–60.8 mm |
| 2.5" | 65 mm | ~75.2–75.5 mm |
To reiterate, these are nominal sizes and are designed to fit matching fittings — not to measure what their name suggests. These are based on PVC Pressure Pipe AS/NZ 1477 Dimensions1.
- º Internal diameters vary slightly by manufacturer and class.
- 1 Not all pool/spa fittings match these dimensions exactly. Some do not follow Australian or international standards. Chinese spas may use proprietary fittings.
Understanding Plumbing Sizes & Nominal Measurements
Plumbing sizes can be confusing. PVC and many other pipe systems use nominal sizes—the size is a name, not the exact measured dimension. This convention is used across most pool and spa systems and other plumbing areas so that pipes and fittings remain compatible.
Why pipe sizes don’t match the measurements
The Nominal Pipe Size (NPS) system standardises pipe dimensions so that pipes, fittings, valves, and accessories interoperate.
Plumbers work with these nominal names every day, but DIYers can be tripped up if they try to match by a tape-measure alone.
How to Measure Pipe Correctly
-
Pipe size is identified by:
- The pipe’s Outside Diameter (OD).
- The fitting’s Inside Diameter (ID) (socket opening).
- Pipe Class / Schedule (e.g., Class 9, 12, 18 or Sch 40) relates to wall thickness and therefore the Internal Diameter (ID) and pressure rating.
- The outside diameter of a fitting is not useful (wall thickness varies by manufacturer).
Hose & Tube Dimensions
Common flexible hose sizes used in pool/spa systems (approximate IDs).
| Imperial Name | Metric Name | Inside Diameter (ID) |
|---|---|---|
| 3/8" | 9–10 mm | ~9 mm |
| 3/4" | 19 mm | ~19 mm |
BSP – British Standard Pipe Thread Sizes
BSP thread names are also nominal. The thread OD will not equal the nominal name.
| BSP Thread Size Naming | Outside Diameter (mm / inch) | TPI |
|---|---|---|
| 1/16" BSP | 7.7 mm / 0.304" | 28 |
| 1/8" BSP | 9.7 mm / 0.383" | 28 |
| 1/4" BSP | 13.16 mm / 0.518" | 19 |
| 3/8" BSP | 16.66 mm / 0.656" | 19 |
| 1/2" BSP / 15 mm | 20.99 mm / 0.825" | 14 |
| 5/8" BSP | 22.99 mm / 0.902" | 14 |
| 3/4" BSP / 20 mm | 26.44 mm / 1.041" | 14 |
| 7/8" BSP | 30.20 mm / 1.189" | 14 |
| 1" BSP / 25 mm | 33.25 mm / 1.309" | 11 |
| 1-1/4" BSP | 41.91 mm / 1.650" | 11 |
| 1-1/2" BSP / 40 mm | 47.80 mm / 1.882" | 11 |
| 2" BSP / 50 mm | 59.61 mm / 2.347" | 11 |
| 2-1/4" BSP | 65.71 mm / 2.587" | 11 |
| 2-1/2" BSP | 75.18 mm / 2.960" | 11 |
| 3" BSP | 87.88 mm / 3.460" | 11 |
| 4" BSP | 113.03 mm / 4.450" | 11 |
| 5" BSP | 138.43 mm / 5.450" | 11 |
| 6" BSP | 163.83 mm / 6.450" | 11 |
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