🏊 Calplas FA-20 720mm Side Mount Sand Filter – 93,000 Litre Pool Capacity

Powerful filtration for large residential pools with industrial-grade durability built to last decades.

🌊 Product Overview

The Calplas FA-20 is a high-capacity industrial-quality polyester sand filter designed for large residential and small commercial swimming pools up to 93,000 litres. With an impressive 720mm tank diameter and 0.39 m² filter area, this side-mount filter delivers outstanding water clarity through its advanced AFM diffusor system, ensuring even water distribution across the entire filter bed for maximum filtration efficiency.

Manufactured by Calplas, an industry leader in pool filtration since 1970, the FA-20 features reinforced fibre-laminated polyester construction with internal steel reinforcement, providing exceptional durability and corrosion resistance for demanding pool environments. The substantial 11.7 m³/h flow rate makes it the ideal choice for pool owners with larger installations who need serious filtration capacity without moving to commercial-grade equipment.

Complete with integrated pressure gauge, automatic air vent, and high-resistance methacrylate transparent lid for easy media inspection, the FA-20 combines professional-grade performance with straightforward maintenance. Backed by a 5-year tank warranty, this filter represents excellent value for owners of large pools seeking long-term reliability.

⭐ Key Features

• ✅ Industrial-Grade Polyester Tank – Reinforced fibre-laminated construction with internal steel reinforcement for exceptional longevity
• ✅ Large 0.39 m² Filter Area – 95% larger than the FA-10 for superior particle capture and extended filter cycles
• ✅ 11.7 m³/h Flow Rate – Powerful capacity handles pools up to 93,000 litres
• ✅ Special AFM Diffusor System – Ensures perfect water distribution, eliminating crater formation and channelling
• ✅ High-Resistance Methacrylate Lid – Transparent cover for visual inspection without disassembly
• ✅ 2.5 Bar Maximum Operating Pressure – Robust design tested to 3.75 bar for safe, reliable operation
• ✅ Integrated ¼” Pressure Gauge – Monitor filter condition at a glance
• ✅ Automatic Air Vent – Eliminates air lock issues automatically
• ✅ Multi-Media Compatible – Accepts sand, gravel, AFM glass media, or ZeoSand
• ✅ 2″ Threaded Connections – Standard sizing for straightforward plumbing integration
• ✅ Temperature Resistant to 40°C – Suitable for heated pools and warm climates
• ✅ 5-Year Tank Warranty – Manufacturer-backed quality assurance

📊 Technical Specifications

Specification	Value
Filter Type	Side Mount Sand Filter
Tank Diameter	720 mm
Tank Height	930 mm
Filter Area	0.39 m²
Flow Rate (Standard @ 30 m³/h/m²)	11.7 m³/h
Flow Rate (Backwash @ 50 m³/h/m²)	19.5 m³/h
Pool Capacity	Up to 93,000 litres (8-hour turnover)
Maximum Operating Pressure	2.5 bar
Test Pressure	3.75 bar
Inlet/Outlet Connections	2″ Female Thread
Filter Opening Diameter	190 mm
Distance from Ground	360 mm
Distance Between Connections	190 mm
Tank Material	Industrial-grade fibre-laminated polyester
Tank Colour	Blue (RAL 5015)
Weight (Empty)	46 kg
Temperature Rating	Up to 40°C
Pressure Gauge	¼” included
Air Vent	Automatic, included
Transparent Lid	Methacrylate, included
Valve Type	6-way valve (sold separately)
Warranty	5 Years (tank)

📐 Pool Sizing Guide

Sizing Principle: The filter flow rate should turn over your 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:

Pool Type	Volume Range	Suitability
🏊 Large above-ground	40,000-60,000 L	✅ Excellent – generous capacity headroom
🏊 Extra-large above-ground	60,000-70,000 L	✅ Ideal – optimal 6-hour turnover
🏠 Medium in-ground	40,000-70,000 L	✅ Excellent – fast efficient turnover
🏠 Large in-ground	70,000-93,000 L	✅ Ideal match with 8-hour turnover
🏠 Very large in-ground	93,000+ L	⚠️ Consider FA-30 or larger model
🏢 Small commercial	Up to 70,000 L	✅ Suitable with appropriate scheduling

This Filter:

📍 Flow Rate: 11.7 m³/h (standard filtration)
📍 Optimal for pools: Up to 70,000 litres (6-hour turnover)
📍 Maximum pool size: 93,000 litres (8-hour turnover)

⚙️ Installation Requirements

Plumbing Connections:

Requirement	Specification
Inlet Connection	2″ Female Thread
Outlet Connection	2″ Female Thread
Valve Position	Side mount
Connection Spacing	190 mm between inlet/outlet

Physical Installation:

Requirement	Details
Base	Solid, level concrete pad or paving required (must support filled weight)
Clearance Above	Minimum 500 mm for lid removal and media inspection
Clearance Around	Minimum 400 mm for valve operation and maintenance
Distance from Ground	360 mm (integrated legs)

Pump Compatibility:

⚠️ Filter must be matched with an appropriate pump.
Recommended pump flow rate: 9-12 m³/h for optimal filtration
Maximum pump flow rate: 19.5 m³/h (backwash capacity)
Pump must not exceed filter's maximum flow rate to avoid media damage.

Valve Requirements:

ℹ️ 6-way multiport valve sold separately
Besgo backwash valve fits as standard
Coupling set required (stated separately)
Optional automatic or manual valve selection available

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🛠️ Maintenance Guide

Routine Maintenance:

Task	Frequency	Procedure
Check pressure gauge	Weekly	Note baseline reading; normal operating range 0.5-1.5 bar
Backwash	When pressure rises 0.3-0.5 bar above baseline	Run until sight glass clears (typically 3-4 minutes)
Rinse after backwash	After each backwash	Run for 30-60 seconds to settle media
Inspect transparent lid	Monthly	Check for cracks, ensure seal integrity
Check seals and O-rings	Seasonally	Replace if worn, cracked, or leaking
Inspect media level	Annually	Top up if settled below recommended level
Full media replacement	Every 5-7 years (sand) / 10+ years (glass)	Replace all media completely

Pressure Gauge Guide:

📊 Clean filter baseline: 0.5-1.0 bar
📊 Backwash recommended: 0.3-0.5 bar above baseline
📊 Maximum safe pressure: 2.5 bar
⚠️ If pressure exceeds 2.5 bar, stop pump immediately and investigate

Winterisation (UK Climate):

• Drain filter tank completely via drain plug
• Remove and store drain plug safely
• Set valve to “Winterise” position if available, or remove valve
• Cover filter or relocate to frost-free storage
• Never leave water in filter during freezing conditions – ice expansion can crack the tank

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🪨 Filter Media Information

Compatible Media Types:

Media Type	Quantity Required	Filtration Rating	Lifespan	Benefits
Sand + Gravel	225 kg sand + 50 kg gravel	20-40 microns	5-7 years	Economical, widely available
AFM Glass Media	210 kg (105 kg Grade 1 + 105 kg Grade 2)	5-15 microns	10+ years	Finer filtration, bio-resistant
ZeoSand	See manufacturer guidelines	3-5 microns	5 years	Superior clarity, ammonia removal

Media Capacity:

• Sand/Gravel: 9 bags (25 kg) sand + 2 bags (25 kg) gravel = 275 kg total
• AFM Glass: 5 bags (21 kg) AFM Grade 1 + 5 bags (21 kg) AFM Grade 2 = 210 kg total

Signs Media Needs Replacing:

• Poor water clarity despite correct chemical balance
• Short filter cycles between backwashes
• Cloudy water returning to pool after filtration
• Visible channelling or cratering in media bed
• Media escaping into pool

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💧 Filtration Performance

Metric	Value
Filter Area	0.39 m²
Standard Flow Rate	11.7 m³/h @ 30 m³/h/m²
Backwash Flow Rate	19.5 m³/h @ 50 m³/h/m²

Filtration Rating by Media:

Media Type	Micron Rating	What It Captures
Sand	20-40 microns	Visible debris, leaves, larger particles
AFM Glass	5-15 microns	Fine particles, most algae, improved clarity
ZeoSand	3-5 microns	Very fine particles, bacteria, exceptional clarity

Micron Rating Guide:

Rating	Particle Size Captured
40+ microns	Visible debris, leaves, hair
20-40 microns	Sand, dirt, visible particles
10-20 microns	Fine particles, some algae spores
5-10 microns	Very fine particles, most algae
Below 5 microns	Microscopic particles, superior water polish

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🔧 Valve Positions & Functions

The Calplas FA-20 requires a 6-way multiport valve (sold separately). Standard valve positions include:

Position	Function	When to Use
Filter	Normal filtration mode	Daily operation – water passes through media and returns clean to pool
Backwash	Reverse flow to clean media	When pressure gauge reads 0.3-0.5 bar above baseline
Rinse	Settle media after backwash	Run for 30-60 seconds after every backwash
Waste	Bypass filter, drain to waste	Vacuuming heavy debris, lowering water level, removing algae
Recirculate	Bypass filter, return to pool	Distributing chemicals quickly, testing pump without filtration
Closed	Stop all water flow	Maintenance, pump basket cleaning, valve servicing

⚠️ Important: Always turn off pump before changing valve position to prevent damage.

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🎯 Ideal Applications

Application	Pool Size	Suitability
🏠 Large residential above-ground	50,000-93,000 L	✅ Excellent choice
🏠 Large residential in-ground	60,000-93,000 L	✅ Ideal for substantial pools
🏡 Holiday letting pool	Up to 80,000 L	✅ Perfect – robust, reliable
🏢 Small commercial/communal	Up to 70,000 L	✅ With appropriate turnover scheduling
🧖 Large swim spa installation	Up to 20,000 L	✅ Generous capacity margin

Best Suited For:

• Owners of large residential pools seeking industrial-quality construction
• Those requiring high flow capacity for pools over 60,000 litres
• Installations where robust, long-lasting equipment is essential
• Holiday rental properties needing reliable, low-maintenance filtration
• Users wanting flexibility to upgrade to glass media for finer filtration

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❓ Frequently Asked Questions

Q: What size pool will this filter handle? A: The Calplas FA-20 is suitable for pools up to 93,000 litres with an 8-hour turnover, or up to 70,000 litres for optimal 6-hour turnover. The 11.7 m³/h flow rate provides excellent filtration for large residential pools.

Q: How does the FA-20 compare to other models in the range? A: The FA-20 offers 95% more filter area than the FA-10 (0.39 m² vs 0.20 m²) and 26% more than the FA-15 (0.39 m² vs 0.31 m²). It’s ideal for pools from 60,000-93,000 litres, bridging the gap between the FA-15 (up to 74,000L) and FA-30 (up to 125,000L).

Q: How often do I need to backwash? A: Backwash when the pressure gauge reads 0.3-0.5 bar above your clean baseline reading. This is typically every 1-2 weeks during swimming season, depending on pool usage and debris levels.

Q: What filter media should I use? A: The FA-20 is compatible with standard pool sand (225 kg + 50 kg gravel), AFM activated filter glass (210 kg), or ZeoSand. Glass media provides finer filtration (5-15 microns vs 20-40 microns for sand) and lasts longer.

Q: How long does filter media last? A: Sand typically lasts 5-7 years with proper maintenance. AFM glass media can last 10+ years due to its bio-resistant properties and resistance to biofilm formation.

Q: What pump do I need? A: Match with a pump delivering 9-12 m³/h for optimal filtration. The maximum pump flow should not exceed 19.5 m³/h (the filter’s backwash capacity). Oversized pumps can damage filter internals and reduce filtration efficiency.

Q: Is the multiport valve included? A: No, the 6-way multiport valve is sold separately. The filter is compatible with standard Besgo backwash valves. Both automatic and manual valve options are available.

Q: What warranty is included? A: The Calplas FA-20 comes with a 5-year manufacturer warranty on the tank. Contact Parts4Tubs for full warranty terms and conditions.

Q: Can I use this filter with saltwater pools? A: Yes, the industrial-grade polyester construction provides excellent resistance to chlorine and saltwater environments.

Q: What colour is the filter tank? A: The tank is finished in blue (RAL 5015). White finish is also available on request.

Q: How heavy is the filter when filled with media? A: The empty weight is 46 kg. When filled with sand and gravel (275 kg), the total weight is approximately 321 kg. Ensure your installation base can support this weight.

📥 Downloads & Resources

📄 Calplas FA Series Technical Datasheet – Complete specifications for all FA models

🏆 Why Choose the Calplas FA-20

• ✅ High Capacity – 0.39 m² filter area handles pools up to 93,000 litres
• ✅ Industrial-Grade Construction – Fibre-laminated polyester with steel reinforcement for 30+ year lifespan
• ✅ Superior Filtration Technology – Special AFM diffusor prevents channelling for consistent water clarity
• ✅ Proven Manufacturer – Calplas has been producing world-class filters since 1970
• ✅ Versatile Media Options – Use sand for economy or upgrade to AFM glass for finer filtration
• ✅ Easy Maintenance – Transparent lid, integrated pressure gauge, and automatic air vent
• ✅ 5-Year Tank Warranty – Peace of mind with manufacturer-backed quality guarantee
• ✅ Excellent Value – Professional performance at competitive pricing

🤝 Why Buy from Parts4Tubs

• ✅ UK-based company with local customer support
• ✅ Fast UK delivery on all orders
• ✅ Expert advice from pool and spa specialists
• ✅ Competitive pricing on all Calplas products
• ✅ Full warranty support and after-sales service
• ✅ Easy returns within 30 days
• ✅ Compatible filter media, valves, and spare parts available
• ✅ Technical support for sizing and installation queries

✨ Summary

The Calplas FA-20 720mm Side Mount Sand Filter delivers powerful industrial-grade filtration for large residential pools up to 93,000 litres. Featuring robust fibre-laminated polyester construction, a generous 0.39 m² filter area, and 11.7 m³/h flow rate, this filter ensures crystal clear water through optimal media distribution. Compatible with sand or glass media and backed by a 5-year tank warranty, the FA-20 offers exceptional performance and long-term value for owners of substantial pools demanding professional-grade equipment