🌊 Certikin Lacron CL18TM 18″ Top Mount Sand Filter – 50,000 Litre Pool Capacity

Effortless pool maintenance with professional-grade filtration, backed by 30 years of proven performance.

💧 Product Overview

The Certikin Lacron CL18TM is a premium 18-inch top mount sand filter engineered for residential swimming pools up to 50,000 litres. This robust filtration system combines 30 years of proven Lacron reliability with modern construction techniques, delivering crystal clear water season after season.

Manufactured from high-grade glass reinforced polyester (GRP), the CL18TM features a hi-gloss, non-corrosive tank that resists UV damage and harsh pool chemicals. The filter comes complete with a six-position multiport valve, pressure gauge, and energy-efficient internal pipework, making it an excellent choice for smaller to medium-sized above-ground or in-ground domestic pools.

The clear view service lid provides convenient access for inspection and maintenance, whilst hydraulically balanced laterals ensure optimal water flow and filtration efficiency throughout the filter’s lifespan.

⭐ Key Features

✅ 30 Years of Proven Performance – Established Lacron engineering trusted across thousands of UK pool installations

✅ Glass Reinforced Polyester Construction – Hi-gloss, non-corrosive GRP tank resists UV damage and chemical exposure

✅ Six-Position Multiport Valve – Complete control with Filter, Backwash, Rinse, Waste, Recirculate, and Closed positions

✅ 8.5 m³/h Maximum Flow Rate – Suitable for pools up to 50,000 litres with efficient 6-8 hour turnover

✅ Clear View Service Lid – 229mm (9″) transparent access lid for easy inspection and maintenance

✅ Hydraulically Balanced Laterals – Maximises water flow distribution and filtration efficiency

✅ Quick Connect Barrel Unions – Speed-style installation and service connections for hassle-free setup

✅ Winter Drain Tap – Easy-access drain for complete winterisation protection

✅ Pressure Tested to 2.5 Bar – Rigorously tested to 4 bar, designed for reliable operation at 2.5 bar maximum

✅ 5-Year Tank Warranty – 1 year full warranty plus 4 years pro-rata on tank, 1 year on components

🔧 Technical Specifications

Specification	Value
Model Number	CL18TM
Filter Type	Top Mount Sand Filter
Pool Capacity	Up to 50,000 litres (50 m³)
Flow Rate (Maximum)	8.5 m³/h
Filter Area	0.166 m²
Filtration Rating	20-40 microns (with standard sand)
Tank Diameter	460 mm (18″)
Overall Height	885 mm
Bed Depth	350 mm
Sand Media Capacity	75 kg
Glass Media Capacity	60 kg
Working Pressure	Maximum 2.5 bar
Test Pressure	4 bar (36 psi)
Valve Size	1½” (50 mm)
Valve Type	6-Position Multiport
Tank Material	Glass Reinforced Polyester (GRP/FRP)
Service Lid Size	229 mm (9″) Clear View
Tank Warranty	5 Years (1 + 4 pro-rata)
Component Warranty	1 Year

📐 Pool Sizing Guide

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

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 20,000 L	✅ Excellent – optimal performance
🏊 Medium above-ground	20,000-40,000 L	✅ Excellent – ideal match
🏊 Large above-ground	40,000-50,000 L	✅ Good – at maximum capacity
🏠 Small in-ground	Up to 30,000 L	✅ Excellent – comfortable headroom
🏠 Medium in-ground	30,000-50,000 L	✅ Good – suitable with proper pump matching
🏠 Large in-ground	50,000+ L	⚠️ Consider larger filter model

This Filter:

📍 Flow Rate: 8.5 m³/h maximum 📍 Suitable for pools up to: 50,000 litres 📍 Optimal pool size: 25,000-40,000 litres for best performance

Example Calculation: A 40,000 litre pool with this filter achieves turnover in approximately 4.7 hours (40 ÷ 8.5 = 4.7), well within the recommended 6-8 hour window.

🔌 Installation Requirements

Plumbing Connections:

Requirement	Specification
Inlet Connection	1½” (50 mm)
Outlet Connection	1½” (50 mm)
Valve Position	Top Mount
Connection Type	Quick Connect Barrel Unions

Physical Installation:

Requirement	Details
Base	Solid, level concrete slab or equivalent firm surface
Position	As close to pool as practical, protected from flooding
Access	Ensure clear access to multiport valve and service lid
Clearance	Allow space for valve operation and backwash line

Pump Compatibility:

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

Pump Specification	Recommendation
Recommended Flow Rate	6-8.5 m³/h
Maximum Flow Rate	Do not exceed 8.5 m³/h
Connection Size	1½” (50 mm) compatible

💡 Tip: Contact Parts4Tubs for pump sizing advice to ensure perfect system matching.

🔄 Maintenance Guide

Routine Maintenance Schedule:

Task	Frequency	Procedure
Check pressure gauge	Weekly	Note reading and compare to baseline
Backwash filter	When pressure rises 0.5 bar above baseline	Until sight glass clears (typically 3-5 mins)
Rinse after backwash	After every backwash	Run for 30-60 seconds
Inspect service lid seal	Monthly	Check for wear or damage
Check media level	Annually	Top up if significantly below normal
Full media replacement	Every 5-7 years (sand)	Replace completely

Pressure Gauge Guide:

📊 Clean filter baseline: Record reading after fresh backwash 📊 Backwash needed: When pressure is 0.5 bar (7 psi) above baseline 📊 Maximum operating pressure: 2.5 bar

Backwash Procedure:

1. Switch off pump
2. Release filter pressure via air release valve
3. Turn multiport valve to BACKWASH position
4. Start pump and run until sight glass shows clear water (approximately 3 minutes)
5. Stop pump, turn valve to RINSE position
6. Run for 30-60 seconds until sight glass clears
7. Stop pump, return valve to FILTER position
8. Resume normal operation and record new baseline pressure

Winterisation (UK Climate):

❄️ Essential steps for frost protection:

• Switch off pump and close inlet valve
• Open air release valve
• Move multiport valve to winterise position (between Filter and Waste)
• Remove drain plug and drain tank completely
• Drain all pipework thoroughly
• Store in frost-free location or cover adequately
• Never leave water in filter during freezing conditions

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🪨 Filter Media Information

Compatible Media Types:

Media Type	Filtration Rating	Lifespan	Capacity Required	Benefits
16/30 Silica Sand	20-40 microns	5-7 years	75 kg	Economical, proven performance
Lacronite (Zeolite)	3-5 microns	5 years	See supplier	Superior water clarity, reduced backwashing
Glass Media	5-15 microns	10+ years	60 kg	Finer filtration, eco-friendly

Media Capacity: 75 kg sand or 60 kg glass media

Recommended Sand Grade: 16/30 (0.5mm to 1.4mm nominal particle size)

Signs Media Needs Replacing:

• Poor water clarity despite correct chemical balance
• Short filter cycles between backwashes
• Increased chemical consumption
• Cloudy water returning to pool after filtration
• Visible channelling in filter bed

🔬 Filtration Performance

Performance Metric	Value
Filter Area	0.166 m²
Bed Depth	350 mm
Standard Filtration	20-40 microns (with sand)
Enhanced Filtration	5-15 microns (with glass media)
Premium Filtration	3-5 microns (with zeolite)

Micron Rating Guide:

Rating	What It Removes
40+ microns	Visible debris, leaves, large particles
20-40 microns	Sand, dirt, visible particles
10-20 microns	Fine particles, some algae spores
5-10 microns	Very fine particles, most algae
3-5 microns	Microscopic particles, bacteria clusters

💡 Upgrade Tip: Switching from sand to glass media can improve filtration from 20-40 microns down to 5-15 microns without any equipment changes.

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⚙️ Valve Positions & Functions

Position	Function	When to Use
FILTER	Normal filtration mode	Day-to-day pool operation
BACKWASH	Reverses flow to clean media	When pressure rises 0.5 bar above baseline
RINSE	Settles media after backwash	Always use after backwashing (30-60 seconds)
WASTE	Bypasses filter to drain	Lowering water level, vacuuming heavy debris
RECIRCULATE	Bypasses filter to pool	Circulating chemicals, troubleshooting
CLOSED	Stops all flow	Pump maintenance (never with pump running)

⚠️ Critical: Always switch off the pump before changing multiport valve position to prevent damage to the spider gasket.

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🎯 Ideal Applications

Application	Pool Size	Suitability
🏠 Residential above-ground	Up to 50,000 L	✅ Excellent – primary application
🏠 Residential in-ground	Up to 50,000 L	✅ Excellent – ideal for domestic installations
🏡 Garden pools	Up to 40,000 L	✅ Excellent – optimal performance range
🏊 Swim spas	Up to 15,000 L	✅ Excellent – more than adequate capacity

Best Suited For:

• First-time pool owners seeking reliable, low-maintenance filtration
• Homeowners upgrading from smaller or older filter systems
• Above-ground pool installations requiring professional-grade equipment
• In-ground domestic pools where space-efficient top mount design is preferred

❓ Frequently Asked Questions

Q: What size pool will this filter handle? A: The CL18TM is suitable for pools up to 50,000 litres (50 m³) with a maximum flow rate of 8.5 m³/h. For optimal performance, it works best with pools between 25,000-40,000 litres.

Q: How often do I need to backwash? A: Backwash when the pressure gauge reads 0.5 bar (7 psi) above your clean baseline reading. This typically occurs every 1-2 weeks depending on pool usage and debris load.

Q: What filter media should I use? A: The filter is compatible with 16/30 grade silica sand (75 kg capacity), glass media (60 kg), or Lacronite zeolite. Sand provides economical 20-40 micron filtration, whilst glass media offers enhanced 5-15 micron filtration.

Q: How long does filter media last? A: Standard sand media typically lasts 5-7 years with proper maintenance. Glass media can last 10+ years. Zeolite should be replaced after approximately 5 years.

Q: What pump do I need? A: Match with a pump delivering 6-8.5 m³/h with 1½” connections. Do not exceed the filter’s maximum flow rate of 8.5 m³/h. Contact Parts4Tubs for specific pump recommendations.

Q: Is this filter suitable for above-ground pools? A: Yes, the CL18TM is ideal for both above-ground and in-ground residential pools up to 50,000 litres.

Q: What warranty is included? A: The tank is covered by a 5-year warranty (1 year full + 4 years pro-rata). All other components including the multiport valve have a 1-year warranty.

Q: How do I winterise this filter? A: Drain all water from the tank and pipework completely. Position the multiport valve between Filter and Waste to allow air circulation. Store in a frost-free location or protect from freezing temperatures.

Q: What is the service lid for? A: The 229mm (9″) clear view service lid provides easy access for visual inspection, media top-ups, and routine maintenance without removing the multiport valve.

Q: Can I upgrade from sand to glass media? A: Yes, glass media is a direct replacement requiring 60 kg (compared to 75 kg sand) and provides improved filtration down to 5-15 microns.

📥 Downloads & Resources

📄 Installation & Operation Manual – Complete installation and operating instructions

📄 Product Brochure (EN/FR/DE/ES) – Full specifications and range information

🏆 Why Choose the Certikin Lacron CL18TM

✅ 30 Years of Proven Performance – Trusted by pool professionals and homeowners across the UK

✅ Premium GRP Construction – Hi-gloss, UV-resistant, non-corrosive tank built to last

✅ Complete Filtration Package – Includes multiport valve, pressure gauge, and all essential components

✅ Optimal Size for Domestic Pools – Perfect capacity for the majority of UK residential installations

✅ Easy Maintenance – Clear view lid, quick-connect unions, and accessible winter drain

✅ Comprehensive Warranty – 5-year tank warranty plus 1-year component coverage

✅ Flexible Media Options – Compatible with sand, glass, or zeolite for customised filtration

✅ Energy Efficient Design – Hydraulically balanced laterals and optimised internal pipework

🤝 Why Buy From Parts4Tubs

✅ UK-Based Company – Local support from pool equipment specialists

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

✅ Expert Advice – Sizing guidance and technical support from experienced professionals

✅ Competitive Pricing – Great value on quality pool filtration equipment

✅ Full Warranty Support – Manufacturer-backed warranties honoured in full

✅ Easy Returns – 30-day returns policy for your peace of mind

✅ One-Stop Shop – Filter media, spare parts, and accessories all available

✨ Summary

The Certikin Lacron CL18TM delivers professional-grade filtration for residential pools up to 50,000 litres. Built from durable glass reinforced polyester with a comprehensive 5-year tank warranty, this top mount sand filter combines 30 years of proven Lacron engineering with practical features including a clear view service lid, 6-position multiport valve, and energy-efficient design. Compatible with sand, glass, or zeolite media for filtration ratings from 20 microns down to 3 microns, the CL18TM offers versatile performance for UK pool owners seeking reliable, low-maintenance water clarity.

Order today and enjoy crystal clear pool water with confidence.