Sensapool SR430 2.0hp - Astralpool CTX 400 Retrofit
Sensapool SR430 2.0hp - Astralpool CTX 400 Retrofit is backordered and will ship as soon as it is back in stock.
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Don't Guess - Ask Us!
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Sensapool SR430 2.0hp - Astralpool CTX 400 Retrofit
Sensapool SR430 2.0hp - Astralpool CTX 400 Retrofit is backordered and will ship as soon as it is back in stock.
Sensapool SR430 2.0hp Pump – Retrofit for Astralpool CTX 400
The Sensapool SR430 2.0hp – Astralpool CTX 400 Retrofit pump is supplied by Spa-Craft, the largest spa parts distributor in the Southern Hemisphere. It is specifically engineered as a direct plumbing replacement for the Astralpool CTX400 pool pump.
Sensapool comes from Spa-Craft - Australia & Southern Hemisphere's largest spa parts distributor and owner of the famous and proven Edgetec bath pump brand. You can be assured they know what they're doing.
This new Sensapool Astralpool retrofit series pump is designed to line up with the existing Astralpool CTX 360pipework in most installations, so in many cases you can swap the old CTX 400 out and fit the SR430 without cutting or re-running plumbing*.
Sensapool SR430 / Astralpool CTX 400 Retrofit Brochure & User Guide (PDF)
Direct Astralpool SR430 replacement
- Purpose built as a retrofit for Astralpool CTX 400 pumps
- Hydraulic performance matched at approximately 400 L/min at 8 m head
- Helps restore correct flow and filtration where an Astralpool CTX 400 has failed
Built for durability and quiet performance
- 316 stainless steel shaft for excellent corrosion resistance in harsh pool environments
- High performance motor for strong, efficient circulation with low noise
- Reliable design suitable for most inground and above ground pools
Easy installation and plumbing compatibility
- Direct plumbing retrofit for Astralpool CTX 400 in most setups
- Supplied with 40 mm and 50 mm barrel unions to suit common pipe sizes
- Ideal for replacing a failing or noisy Astralpool CTX 400 with minimal installation time
Warranty
3 year parts
1 year mechanical seal
1 year onsite labour
*Refer to manufacturer’s terms and conditions.
In plumbing, named sizes are not the actual measurements. A pipe called “50mm” or “2"” does not measure 50 mm across. Instead, it follows nominal sizing, an internationally-standardised naming system.
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 |
These are nominal sizes and are designed to fit matching fittings — not to measure exactly 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 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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SP-SR430