🏊 Calplas DCH/P 520 Commercial Pool Filter – High-Performance AFM/Sand Filtration

Effortless pool maintenance with professional-grade filtration for medium to large pools

🌊 Product Overview

The Calplas DCH/P 520 is a commercial-grade pool filter constructed from hand-laminated glass-reinforced polyester (GRP) by Calplas, Spain’s leading filtration vessel manufacturer with expertise spanning over five decades since 1970. This high-performance filter features a 1200mm deep filter bed, delivering superior particle capture and extended filtration cycles compared to standard residential units.

Engineered for pools up to approximately 48,000 litres, the DCH/P 520 represents the mid-range sweet spot in the DCH/P series, offering substantial 6 m³/h flow capacity through its 0.20 m² filter area. The 520mm diameter tank provides excellent filtration performance for larger residential pools, holiday rentals, and small commercial installations.

Featuring internal steel reinforcement, a steel-reinforced nozzle plate, and compatibility with both sand and AFM® glass media, this filter is built for demanding, long-term operation. Each unit includes a lateral service manhole, integrated sight glass, and transparent top lid with vent connection. Handmade to order in Spain and backed by a comprehensive 5-year tank warranty.

💫 Key Features

• ✅ Industrial GRP Tank – Hand-laminated glass-reinforced polyester ensures exceptional longevity and corrosion resistance
• ✅ 1200mm Deep Filter Bed – Extended media depth provides superior filtration and longer cycles between backwashes
• ✅ Steel-Reinforced Nozzle Plate – Robust construction for reliable, even water distribution
• ✅ Internal Steel Reinforcement – Commercial-grade structural integrity for demanding applications
• ✅ Dual Media Compatibility – Special diffuser optimised for both sand and AFM® glass media
• ✅ Integrated 2″ Connections – Female GAS threads moulded directly into the filter body
• ✅ 305mm Service Manhole – Lateral access for easy media inspection and replacement
• ✅ 2½” Sight Glass Included – Monitor backwash clarity without guesswork
• ✅ Transparent Top Lid – With 3/4″ female vent connection for air release
• ✅ EN 13121-3 Compliant – Manufactured to European pressure vessel standards
• ✅ 5-Year Tank Warranty – Comprehensive manufacturer protection

📊 Technical Specifications

Specification	Value
Filter Type	High-Bed Sand/AFM® Filter
Tank Diameter	520 mm
Overall Height	1832 mm
Filter Bed Height	1200 mm
Filter Area	0.20 m²
Sand Capacity (Total)	325 kg
AFM® Capacity (Total)	273 kg
Flow Rate (Standard @ 30 m³/h/m²)	6 m³/h
Flow Rate (Backwash @ 50 m³/h/m²)	10 m³/h
Inlet/Outlet Connection	2″ Female (GAS thread)
Filter Opening (Top)	ø 190 mm
Service Manhole	ø 305 mm
Sight Glass	2½”
Distance: Ground to Bottom Connection	300 mm
Distance Between Connections	1237 mm
Tank Material	GRP (Glass Reinforced Polyester)
Maximum Operating Pressure	2.5 bar
Test Pressure	3.75 bar
Maximum Temperature	40°C
Weight (Empty)	72 kg
Colour	Blue RAL 5015 (White available on request)
Warranty	5 Years Tank Warranty

📐 Pool Sizing Guide

Sizing Principle: The filter flow rate should turn over the entire pool volume within 6-8 hours for optimal water clarity and hygiene.

Formula:

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

Pool Size Compatibility for DCH/P 520:

Pool Type	Volume Range	Suitability
🏠 Medium residential	Up to 35,000 L	✅ Excellent – fast turnover
🏠 Large residential	35,000-48,000 L	✅ Good – standard 8-hour turnover
🌊 Large above-ground pools	Up to 40,000 L	✅ Ideal sizing
🏢 Small commercial	Up to 36,000 L	✅ Meets 6-hour turnover requirement

This Filter:

📍 Standard Flow Rate: 6 m³/h (at 30 m³/h/m²)
📍 Backwash Flow Rate: 10 m³/h (at 50 m³/h/m²)
📍 Optimal Pool Size: Up to 36,000 litres (6-hour turnover)
📍 Maximum Pool Size: Up to 48,000 litres (8-hour turnover)

💡 Tip: The DCH/P 520 offers 25% more flow capacity than the 460 model, making it ideal for pools between 38,000-48,000 litres.

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⚙️ Installation Requirements

Plumbing Connections:

Requirement	Specification
Inlet Connection	2″ Female (GAS thread)
Outlet Connection	2″ Female (GAS thread)
Vent Connection	3/4″ Female (on transparent lid)
Connection Position	Lateral (side-mounted)

Physical Installation:

Requirement	Details
Base	Solid, level concrete pad required
Clearance Above	Minimum 500 mm for lid removal and maintenance
Clearance Around	Minimum 450 mm for service access
Manhole Access	305 mm lateral manhole – ensure clear access

Pump Compatibility:

⚠️ Important: Filter must be matched with an appropriate pump for optimal performance.

Parameter	Requirement
Recommended Pump Flow Rate	5.0 – 6.0 m³/h
Backwash Pump Requirement	Up to 10 m³/h
Maximum System Pressure	Do not exceed 2.5 bar operating pressure

💡 Note: Backwash valve and front tube system sold separately. Available in automatic or manual selection options.

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🔄 Maintenance Guide

Routine Maintenance Schedule:

Task	Frequency	Procedure
Check pressure gauge	Weekly	Record baseline and monitor increases
Backwash filter	When pressure rises 0.5-0.7 bar above baseline	Run until sight glass shows clear water
Rinse after backwash	After every backwash	30-60 seconds to settle media
Inspect seals and gaskets	Seasonally	Replace if showing wear or damage
Check media level	Annually	Top up if settlement has occurred
Full media replacement	Sand: 5-7 years / AFM®: 10+ years	Replace completely when filtration degrades

Pressure Gauge Guide:

Reading	Status
📊 Baseline (clean filter)	Typically 0.5-0.8 bar
📊 Backwash needed	0.5-0.7 bar above baseline
📊 Maximum safe operating	2.5 bar

⚠️ Warning: Never exceed 2.5 bar operating pressure. If pressure continues to rise after backwashing, inspect for blockages or media issues.

Winterisation (UK Climate):

For UK installations, proper winterisation is essential to prevent frost damage:

• Drain filter tank completely via the drain plug
• Remove and safely store the drain plug
• Leave multiport valve in “Winterise” position if equipped
• Cover filter or relocate to frost-free storage
• Never leave water standing in the filter during freezing conditions

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🪨 Filter Media Information

The Calplas DCH/P 520 is designed for both traditional sand and advanced AFM® (Activated Filter Media) with a special internal diffuser optimised for both media types.

Compatible Media Types:

Media Type	Filtration Rating	Lifespan	Key Benefits
Filter Sand	20-40 microns	5-7 years	Economical, proven performance
Glass Media (AFM®)	5-15 microns	10+ years	Finer filtration, longer life, reduced chlorine demand
ZeoSand	3-5 microns	5 years	Superior clarity, ammonia absorption

Media Capacity for DCH/P 520:

Media Type	Bags Required	Total Weight
AFM® (21 kg bags)	G3: 0 / G2: 3 / G1: 10	273 kg
Sand (25 kg bags)	Coarse: 0 / Medium: 3 / Fine: 10	325 kg

💡 Layering Guide: When filling, add coarsest grade first (bottom), then medium, then finest grade (top). This creates optimal filtration depth and backwash efficiency.

Signs Media Needs Replacing:

• Poor water clarity despite correct chemical balance
• Shortened filter cycles between backwashes
• Cloudy water returning to pool during filtration
• Media visible in pool (indicates broken laterals)
• Filter sand clumping or channelling

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✨ Filtration Performance

Metric	Value
Filter Area	0.20 m²
Filter Bed Height	1200 mm
Standard Flow Rate	6 m³/h
Filtration Rating	Depends on media selected

Micron Rating by Media Type:

Media Selection	Filtration Rating	What It Catches
Standard Sand	20-40 microns	Visible debris, sand, dirt, larger particles
AFM® Grade 1	10-15 microns	Fine particles, some algae spores
AFM® (full bed)	5-10 microns	Very fine particles, most algae, improved clarity
ZeoSand	3-5 microns	Ultra-fine particles, bacteria, superior clarity

High-Bed Advantage:

The 1200mm filter bed height provides significantly better filtration compared to standard 450-600mm residential filters. Benefits include:

• Extended contact time between water and media
• Improved particle capture efficiency
• Longer periods between backwashes
• Better handling of peak bather loads

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🔧 Valve Positions & Functions

The DCH/P 520 requires a separate multiport valve (not included). Standard 6-position multiport valve functions:

Position	Function
Filter	Normal filtration – water passes through media to pool
Backwash	Reverse flow to clean media – discharge to waste
Rinse	Settle media after backwash – discharge to waste
Waste	Bypass filter – drain pool directly to waste
Recirculate	Bypass filter – return water to pool without filtering
Closed	Stop all water flow through valve

⚠️ Note: Backwash valve/front tube system is sold separately. Available in automatic or manual configurations.

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🎯 Ideal Applications

Application	Pool Size	Suitability
🏠 Large residential in-ground pools	Up to 48,000 L	✅ Excellent
🏠 Large above-ground pools	Up to 40,000 L	✅ Excellent
🏢 Small commercial pools	Up to 36,000 L	✅ Good (6-hour turnover)
🏨 Holiday let / rental properties	Up to 45,000 L	✅ Excellent durability
🏫 School / institution pools	Up to 36,000 L	✅ Commercial-grade reliability
♨️ Swim spas / large spas	Up to 30,000 L	✅ Ideal with fast turnover

Best Suited For:

• Larger residential pools requiring commercial-grade filtration
• Pool owners with 38,000-48,000 litre pools
• Installations where the 460 model is borderline for capacity
• AFM® filtration system upgrades
• Properties with high bather loads requiring robust filtration

❓ Frequently Asked Questions

Q: What size pool will this filter handle? A: The DCH/P 520 is suitable for pools up to 48,000 litres with an 8-hour turnover, or up to 36,000 litres for the optimal 6-hour commercial turnover rate.

Q: How does this compare to the DCH/P 460? A: The 520 offers 25% more flow capacity (6 vs 4.8 m³/h) and 25% more filter area (0.20 vs 0.16 m²), suitable for pools up to 10,000 litres larger.

Q: How often do I need to backwash? A: Backwash when the pressure gauge reads 0.5-0.7 bar above your clean baseline reading, typically every 1-2 weeks depending on pool usage and debris load.

Q: What filter media should I use? A: The filter is compatible with both sand (325 kg capacity) and AFM® glass media (273 kg capacity). AFM® provides finer filtration and longer lifespan, while sand is more economical.

Q: How long does filter media last? A: Sand typically lasts 5-7 years; AFM® glass media can last 10+ years with proper maintenance.

Q: What pump do I need? A: Match with a pump delivering 5.0-6.0 m³/h for standard filtration. Ensure your pump can deliver up to 10 m³/h for effective backwashing. Never exceed the filter’s 2.5 bar maximum operating pressure.

Q: Is the multiport valve included? A: No, the backwash valve and front tube system are sold separately. Both automatic and manual options are available.

Q: What warranty is included? A: The filter comes with a 5-year tank warranty from Calplas.

Q: How long is delivery? A: As these filters are handmade to order in Spain, please allow 4-6 weeks for delivery.

Q: Is a pressure gauge included? A: No, the pressure gauge and vent are not included and should be purchased separately.

📥 Downloads & Resources

📄 Calplas DCH/P Technical Datasheet – Complete specifications and dimensions

🏆 Why Choose the Calplas DCH/P 520

• ✅ 50+ Years Manufacturing Excellence – Calplas expertise since 1970
• ✅ Handcrafted Quality – Individually made in Spain to exacting standards
• ✅ Commercial-Grade Construction – Steel-reinforced GRP to EN 13121-3 standards
• ✅ Superior 1200mm Bed Height – Outperforms standard residential filters
• ✅ Versatile Media Options – Optimised for both sand and AFM® glass media
• ✅ Mid-Range Powerhouse – Ideal for pools 38,000-48,000 litres
• ✅ 5-Year Tank Warranty – Comprehensive protection included

🤝 Why Buy from Parts4Tubs

• ✅ UK-based company with dedicated local support
• ✅ Fast UK delivery on in-stock items
• ✅ Expert advice from pool and spa specialists
• ✅ Competitive pricing on commercial filtration equipment
• ✅ Full warranty support handled in the UK
• ✅ Easy returns within 30 days
• ✅ Compatible accessories – filter media, valves, and spare parts available
• ✅ Technical guidance for sizing and installation queries

⭐ Summary

The Calplas DCH/P 520 delivers commercial-grade filtration for pools up to 48,000 litres. Featuring a 1200mm high filter bed, 0.20 m² filter area, and robust 6 m³/h flow rate, this steel-reinforced GRP filter provides outstanding water clarity for larger residential and small commercial pools. Compatible with both sand (325 kg) and AFM® media (273 kg), and backed by a 5-year tank warranty, the DCH/P 520 is the ideal mid-range solution for demanding pool owners who refuse to compromise on filtration quality.