💧 Calplas HFS-6 415mm Side Mount Sand Filter – Up to 31,000 Litre Pool Capacity

Crystal clear water for your pool, season after season

📋 Product Overview

The Calplas HFS-6 is a compact yet powerful industrial-quality polyester sand filter, perfectly sized for smaller residential pools and above-ground installations. Featuring a 415mm diameter tank constructed from hand-laid glass reinforced polyester (GRP) with internal steel reinforcement, this Spanish-manufactured filter delivers the same exceptional build quality and reliability as its larger siblings in a space-efficient package.

The HFS series is distinguished by its significantly taller design compared to standard filters, containing almost 50% more filter medium. This extended filter bed height provides increased water contact time, resulting in superior filtration efficiency and enhanced flocculation for consistently clear pool water throughout the swimming season.

Despite its compact dimensions, the HFS-6 incorporates a special AFM diffusor for ideal water distribution across the filter bed, preventing crater formation and ensuring uniform filtration performance. The transparent lid allows easy visual inspection of the media condition. Capable of handling pools up to 31,000 litres with an 8-hour turnover, the HFS-6 is the ideal choice for smaller in-ground pools, above-ground pools, and swim spas where quality filtration is essential but space may be limited.

💫 Key Features

✅ Industrial-Quality GRP Construction – Hand-laid glass reinforced polyester tank with internal steel reinforcement, manufactured to EN 13121-3 standards

✅ 50% More Filter Medium – Taller tank design provides almost 50% more media capacity than standard filters of similar diameter

✅ Compact 415mm Diameter – Space-efficient design ideal for smaller installations and equipment rooms

✅ 190mm Transparent Lid – Clear inspection port for easy visual monitoring of filter media condition

✅ Special AFM Diffusor – Engineered water distribution system prevents crater formation for consistent filtration

✅ 2.5 Bar Operating Pressure – Industrial-grade pressure rating with 3.75 bar test pressure (7 bar versions available on request)

✅ 6-Way Valve Compatible – Accepts exclusive Calplas 6-way multiport valve with automatic or manual selection; Besgo backwash valve fits as standard

✅ Dual Media Compatibility – Works with traditional sand/gravel or advanced AFM activated filter media

✅ 40°C Temperature Rating – Suitable for heated pools, swim spas, and warm climate installations

✅ Complete Filter Package – Includes pressure gauge, air vent, drain plug, and transparent lid as standard

✅ 5-Year Tank Warranty – Comprehensive manufacturer warranty for peace of mind

✅ White Option Available – Alternative colour to suit your installation preferences

🔧 Technical Specifications

Specification	Value
Filter Type	Sand / AFM Media Filter
Tank Diameter	415 mm
Overall Height	861 mm
Filter Area	0.13 m²
Flow Rate (Normal Filtration)	3.9 m³/h (at 30 m³/h/m²)
Flow Rate (Backwash Capacity)	6.5 m³/h (at 50 m³/h/m²)
Pool Capacity (6-hr Turnover)	Up to 23,000 litres
Pool Capacity (8-hr Turnover)	Up to 31,000 litres
Sand Capacity	3 kg sand + 1 kg gravel
AFM Media Capacity	3 × 21 kg bags Grade 1 + 2 × 21 kg bags Grade 2
Maximum Operating Pressure	2.5 bar
Test Pressure	3.75 bar
Temperature Rating	Up to 40°C
Inlet/Outlet Connections	2″ (50 mm) threaded
Filter Opening Diameter	190 mm
Distance from Ground	260 mm
Distance Between Connections	190 mm
Tank Material	Hand-laid GRP (Glass Reinforced Polyester)
Reinforcement	Internal steel reinforced
Weight (Empty)	15 kg
Valve Type	Side mount (6-way valve optional)
Warranty	5 years (tank)
Product Code	1519250106
Manufacturer	Calplas (Spain)
Manufacturing Standard	EN 13121-3

📐 Pool Sizing Guide

Sizing Principle: The filter flow rate should achieve complete pool water turnover within 6-8 hours for optimal clarity and hygiene.

Formula:

Required Flow Rate (m³/h) = Pool Volume (m³) ÷ Turnover Time (hours)

Pool Size Compatibility:

Pool Type	Volume Range	Suitability
🏊 Small above-ground	Up to 15,000 L	✅ Excellent – generous capacity
🏊 Medium above-ground	15,000 – 23,000 L	✅ Excellent – optimal match
🏊 Large above-ground	23,000 – 31,000 L	✅ Good – within maximum
🏠 Small in-ground	Up to 23,000 L	✅ Excellent – ideal match
🧖 Swim spas	Up to 15,000 L	✅ Excellent – perfect size
🏠 Plunge pools	Up to 20,000 L	✅ Excellent

This Filter:

📍 Normal Filtration Flow Rate: 3.9 m³/h
📍 Maximum Backwash Flow Rate: 6.5 m³/h
📍 Recommended Pool Size: Up to 23,000 litres (6-hour turnover)
📍 Maximum Pool Size: Up to 31,000 litres (8-hour turnover)

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🛠️ Installation Requirements

Plumbing:

Requirement	Specification
Inlet Connection	2″ (50 mm) female thread
Outlet Connection	2″ (50 mm) female thread
Connection Spacing	190 mm between ports
Valve Position	Side mount

Physical Installation:

Requirement	Details
Base	Solid, level surface required
Minimum Height Clearance	600 mm above filter for lid removal
Distance from Ground	260 mm (integrated legs)
Access Clearance	400 mm all around for maintenance
Weight Consideration	15 kg empty – easy to position

Pump Compatibility:

⚠️ Important: Filter must be paired with an appropriately sized pump.

Parameter	Specification
Recommended Pump Flow Rate	2.5 – 4 m³/h
Maximum Pump Flow Rate	Do not exceed 6.5 m³/h
Pump Head	Allow for filter pressure drop

💡 Tip: For optimal filtration, select a pump at the lower end of the flow range. Slower flow rates improve particle capture and water clarity.

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🔄 Maintenance Guide

Routine Maintenance:

Task	Frequency	Procedure
Check pressure gauge	Weekly	Record baseline; monitor for increases
Backwash filter	When pressure rises 0.5-1 bar	Run until sight glass clears (1-2 minutes)
Rinse after backwash	After every backwash	Run for 20-30 seconds to settle media
Inspect transparent lid	Monthly	Check for cracks, seal condition
Check O-rings and seals	Seasonally	Replace if worn or leaking
Inspect media level	Annually	Top up if settled
Full media replacement	5-7 years (sand) / 10-15 years (AFM)	Complete media change

Pressure Gauge Guide:

📊 Clean filter baseline: Record pressure after backwash
📊 Backwash trigger: 0.5-1 bar above baseline
📊 Maximum operating pressure: 2.5 bar – never exceed

Winterisation (UK Climate):

❄️ Essential winter protection steps:

1. Turn off pump and isolate electrical supply
2. Close inlet and outlet valves
3. Set multiport valve to “Winterise” or between positions
4. Drain filter tank completely via drain plug
5. Remove drain plug and store indoors
6. Leave air vent open
7. Cover filter or store in frost-free location
8. Never leave water in filter during freezing conditions

⚠️ Warning: Frost damage from residual water is not covered under warranty.

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🪨 Filter Media Information

Compatible Media Types:

Media Type	Filtration Rating	Lifespan	Key Benefits
Silica Sand	20-40 microns	5-7 years	Economical, proven, easy to source
Glass Media	10-15 microns	10+ years	Finer filtration, lighter, eco-friendly
AFM (Activated Filter Media)	1-5 microns	10-15 years	Superior clarity, self-sterilising, reduced chemicals
ZeoSand	3-5 microns	5 years	Excellent clarity, ammonia removal

Media Capacity for HFS-6:

Media Type	Quantity Required
Sand + Gravel	3 kg sand (0.4-0.8 mm) + 1 kg gravel (2-4 mm)
AFM Media	3 × 21 kg Grade 1 + 2 × 21 kg Grade 2 (105 kg total)

💡 Note: The HFS-6 includes a special AFM diffusor, making it well-suited for AFM media upgrades. AFM provides filtration down to 1 micron and a 10-15 year media lifespan.

Signs Media Needs Replacing:

• Poor water clarity despite correct chemical balance
• Short filter cycles between backwashes
• Cloudy water returning to pool
• Media particles in pool water
• Increased chemical consumption

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🔬 Filtration Performance

Metric	Value
Filter Area	0.13 m²
Filtration Rating (Sand)	20-40 microns
Filtration Rating (AFM)	1-5 microns

Micron Rating Guide:

Rating	Particle Types Removed
40+ microns	Leaves, visible debris, large particles
20-40 microns	Sand, dirt, visible suspended particles
10-20 microns	Fine particles, some algae spores
5-10 microns	Very fine particles, most algae
1-5 microns	Ultra-fine particles, bacteria, all algae

Enhanced Filtration Design:

The HFS-6’s taller filter bed delivers almost 50% more media contact time than standard compact filters. Benefits include:

✅ Better flocculation of fine particles
✅ Improved removal of suspended solids
✅ Enhanced water clarity
✅ Reduced chemical requirements
✅ Longer intervals between backwashes

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⚙️ Valve Positions & Functions

The HFS-6 accepts a 6-way multiport valve (sold separately) with these functions:

Position	Function
Filter	Normal filtration – water flows through media to pool
Backwash	Reverses flow to flush debris to waste
Rinse	Settles media after backwash
Waste	Bypasses filter – water to drain
Recirculate	Bypasses filter – water returns to pool
Closed	Stops all water flow

💡 Note: Besgo backwash valve fits as standard. Coupling set sold separately. Calplas 6-way valves available in automatic or manual versions.

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🎯 Ideal Applications

Application	Pool Size	Suitability
🏊 Above-ground pools	Up to 31,000 L	✅ Excellent
🏠 Small in-ground pools	Up to 23,000 L	✅ Excellent
🧖 Swim spas	Up to 15,000 L	✅ Excellent
🏠 Plunge pools	Up to 20,000 L	✅ Excellent
🏡 Holiday home pools	Up to 25,000 L	✅ Good
🏠 Courtyard pools	Up to 20,000 L	✅ Excellent

Best Suited For:

• Smaller residential pools requiring quality filtration
• Above-ground pool installations
• Swim spas and plunge pools
• Compact equipment rooms with limited space
• Budget-conscious installations without compromising quality
• Properties where AFM media upgrade is planned

❓ Frequently Asked Questions

Q: What size pool will this filter handle?

A: The HFS-6 is suitable for pools up to 31,000 litres with an 8-hour turnover, or up to 23,000 litres for optimal 6-hour turnover. With a 3.9 m³/h flow rate, it’s ideal for smaller residential pools, above-ground pools, and swim spas.

Q: How often should I backwash?

A: Backwash when the pressure gauge reads 0.5-1 bar above your clean baseline. This is typically every 1-2 weeks during swimming season, varying with usage and debris levels.

Q: What filter media should I use?

A: The HFS-6 accommodates 3 kg sand plus 1 kg gravel, or AFM media totalling 105 kg (3 bags Grade 1 + 2 bags Grade 2). The integrated AFM diffusor makes this filter well-suited for AFM upgrades.

Q: How long does filter media last?

A: Sand typically lasts 5-7 years. Glass media and AFM last 10-15 years with proper maintenance.

Q: What pump do I need?

A: Select a pump delivering 2.5-4 m³/h for optimal filtration. Never exceed 6.5 m³/h.

Q: What warranty is included?

A: The HFS-6 includes a 5-year tank warranty from Calplas. Contact Parts4Tubs for full terms.

Q: Is this suitable for saltwater pools?

A: Yes, the GRP construction provides excellent saltwater corrosion resistance.

Q: How does the HFS-6 compare to larger HFS models?

A: The HFS-6 uses the same industrial-quality construction and includes the AFM diffusor, but in a compact 415mm diameter. It has a 190mm lid (vs 305mm+ on HFS-15 and above) and handles smaller pool volumes.

Q: Is the multiport valve included?

A: No, the 6-way valve is sold separately. Besgo backwash valve fits as standard; coupling set required separately.

Q: Can I upgrade from sand to AFM media later?

A: Yes, the HFS-6 is designed to work with AFM media. Simply drain, remove old media, and refill with AFM following the recommended grade configuration.

📥 Downloads & Resources

📄 Calplas HFS Filter Specifications (PDF) – Complete technical specifications for the entire HFS filter range

✅ Why Choose the Calplas HFS-6

✅ Compact Yet Capable – 0.13 m² filter area with 3.9 m³/h flow rate handles pools up to 31,000 litres

✅ 50% More Filter Medium – Taller design provides extended contact time for superior clarity

✅ Industrial-Grade Construction – Hand-laid GRP with steel reinforcement to EN 13121-3 standards

✅ Space-Efficient Design – 415mm diameter fits smaller equipment areas

✅ Lightweight – Just 15 kg empty for easy handling and installation

✅ AFM Compatible – Integrated diffusor supports upgrade to 1-micron filtration

✅ 5-Year Tank Warranty – Comprehensive manufacturer coverage

✅ Proven Spanish Engineering – Manufactured by Calplas filtration specialists

🤝 Why Buy From Parts4Tubs

✅ UK-Based Company – Local support from pool and spa specialists

✅ Fast UK Delivery – Quick dispatch to get your pool running

✅ Expert Advice – Technical guidance on sizing and installation

✅ Competitive Pricing – Great value on quality equipment

✅ Full Warranty Support – Direct manufacturer warranty handling

✅ Easy Returns – 30-day returns policy

✅ Complete Range – Filter media, valves, and spare parts available

✅ Trusted Supplier – Established pool equipment retailer

🌟 Summary

The Calplas HFS-6 415mm Side Mount Sand Filter delivers professional-grade filtration in a compact package for pools up to 31,000 litres. Built with industrial-quality hand-laid GRP construction and internal steel reinforcement to EN 13121-3 standards, this Spanish-engineered filter features 50% more media capacity than standard compact filters. With a 3.9 m³/h flow rate, 0.13 m² filter area, and compatibility with both sand and AFM media (filtration down to 1 micron), the HFS-6 is ideal for smaller in-ground pools, above-ground pools, and swim spas. Lightweight at just 15 kg and backed by a 5-year tank warranty.

Order today for crystal-clear water in your smaller pool.