🌊 Certikin FDB750 Deep Bed Sand Filter with Multiport Valve – 750mm Diameter, 22m³/h Flow Rate

The flagship deep bed filter delivering exceptional filtration for large pools and demanding applications

📋 Product Overview

The Certikin FDB750 Deep Bed Sand Filter is the flagship model in Certikin’s premium deep bed filtration range, engineered for large residential pools, busy family installations, and light commercial applications demanding uncompromising water quality. With an impressive 750mm diameter tank, powerful 22m³/h flow rate, and substantial 518kg media capacity, the FDB750 delivers the ultimate in deep bed filtration performance.

This high-capacity filter features Certikin’s signature extended media bed depth, ensuring water remains in contact with filter media significantly longer than standard filters. The result is exceptional particle capture, superior dirt retention, and crystal-clear water that lasts between maintenance cycles. For pool owners with larger installations who demand professional-grade results, the FDB750 represents the pinnacle of domestic deep bed filtration technology.

Manufactured using advanced bobbin-wound fibreglass and polyester resin construction, the FDB750 delivers the strength and corrosion resistance necessary for years of reliable service. The factory-fitted side-mount 6-way multiport valve with 2″ connections ensures seamless integration with larger pool circulation systems. Whether you’re maintaining a substantial in-ground pool, a holiday property, or a busy family pool requiring reduced maintenance intervals, the FDB750 delivers the performance and reliability that discerning UK pool owners expect from Certikin.

💫 Key Features

✅ Maximum Deep Bed Capacity – The largest model in the FDB range with 518kg media capacity for exceptional dirt retention and extended filtration cycles

✅ Powerful 22m³/h Flow Rate – Handles large pools up to 176,000 litres with efficient turnover times

✅ 750mm Diameter Tank – Generous 0.44m² filtration area provides superior particle capture and extended backwash intervals

✅ Professional-Grade Construction – Bobbin-wound fibreglass reinforced polyester resin delivers exceptional durability and corrosion resistance

✅ 2″ Connection Size – Larger bore connections reduce flow restriction for optimal hydraulic efficiency on bigger pools

✅ Side-Mount Multiport Valve Included – Factory-fitted 6-way valve for intuitive operation across all filtration and maintenance functions

✅ Integrated Pressure Gauge – Accurate monitoring enables precise backwash timing for peak efficiency

✅ Manual Air Vent – Releases trapped air to maintain consistent filtration performance

✅ Manual Water Drain – Essential for complete winterisation in UK climate conditions

✅ 2.5 Bar Maximum Working Pressure – Robust pressure rating accommodates powerful pump configurations

✅ Multi-Media Compatible – Accepts sand, glass media, or zeolite for customised filtration solutions

✅ Light Commercial Suitability – Capable of handling small commercial or high-use residential applications

🔩 Technical Specifications

Specification	Value
Filter Type	Deep Bed Sand Filter
Model	FDB750
Tank Diameter	750mm
Connections	2″ (50mm)
Flow Rate	22m³/h (21,000 L/h)
Filtration Area	0.44m²
Filtration Rating	20-40 microns (with sand media)
Media Capacity	518kg
Maximum Working Pressure	2.5 bar
Tank Material	Fibreglass reinforced polyester resin
Valve Type	6-way side-mount multiport
Valve Included	Yes
Pressure Gauge	Included
Air Vent	Manual
Water Drain	Manual
Manufacturer	Certikin (Fluidra Group)

📏 Pool Sizing Guide

The Certikin FDB750 is the ultimate choice for large residential pools and demanding applications, providing optimal water clarity when correctly matched to pool volume. Pool filtration systems should turn over the entire pool volume within 6-8 hours for residential installations.

Sizing Calculation:

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

Pool Size Compatibility:

Pool Type	Volume Range	Suitability
🏠 Large In-Ground	80,000-130,000 L	✅ Excellent – optimal performance
🏠 Very Large In-Ground	130,000-176,000 L	✅ Very Good – suitable with 8-hour turnover
🏊 Large Above-Ground	60,000-100,000 L	✅ Excellent – premium performance
🏡 Holiday Let Pools	Up to 130,000 L	✅ Ideal – reduced maintenance
🏢 Light Commercial	Up to 130,000 L	✅ Good – verify against regulations
🧖 Commercial Swim Spas	20,000-40,000 L	✅ Premium Choice

This Filter:

📍 Flow Rate: 22m³/h
📍 Optimal Pool Size: Up to 132,000 litres (6-hour turnover)
📍 Maximum Pool Size: Up to 176,000 litres (8-hour turnover)

💡 Tip: For commercial or high bather-load applications, always verify filtration requirements against PWTAG guidelines or consult with a pool professional.

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⚙️ Installation Requirements

Plumbing Connections:

Requirement	Specification
Inlet Connection	2″ (50mm)
Outlet Connection	2″ (50mm)
Valve Position	Side mount
Union Type	Standard threaded

Physical Installation:

Requirement	Details
Base	Heavy-duty concrete pad essential – must support substantial filled weight
Clearance Above	Minimum 600mm for valve operation and maintenance
Clearance Around	Minimum 500mm on all sides for access
Location	Protect from direct sunlight where possible
Weight Planning	Account for tank + 518kg media + water when filled

Pump Compatibility:

⚠️ Important: The FDB750 requires a suitably powerful pump to achieve optimal performance. Correct pump sizing is essential.

Parameter	Recommendation
Recommended Pump Flow	15.0 – 22.0m³/h
Maximum Pump Flow	Do not exceed 22m³/h
Pump Power	Typically 1.5hp – 2.0hp depending on system
Connection Size	2″ pipework recommended

💡 Note: With 2″ connections, the FDB750 is designed for larger circulation systems. Ensure all pipework is appropriately sized to avoid flow restriction and maximise efficiency.

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🔄 Maintenance Guide

Routine Maintenance Schedule:

Task	Frequency	Method
Check pressure gauge	Weekly	Note baseline reading when clean
Backwash filter	When pressure rises 0.5-0.7 bar above clean baseline	Run until sight glass clears (typically 3-5 minutes)
Rinse after backwash	After every backwash	60-90 seconds to settle media
Inspect valve seals	Seasonally	Replace if worn or leaking
Check media level	Annually	Top up if low
Full media replacement	Every 5-7 years (sand)	Replace completely

Pressure Gauge Guide:

📊 Clean filter baseline: 0.8-1.2 bar (typical)
📊 Backwash recommended: 0.5-0.7 bar above baseline
📊 Maximum operating: 2.5 bar

⚠️ Warning: Never exceed the maximum working pressure of 2.5 bar. The FDB750’s large media capacity means backwashing uses significant water – ensure adequate drainage capacity.

Winterisation (Essential for UK Climate):

1. Switch off pump and allow system to depressurise
2. Set multiport valve to “Winterise” or between positions
3. Drain filter tank completely via manual drain – allow adequate time for 518kg media bed
4. Remove and store drain plug safely
5. Leave multiport valve in intermediate position to prevent seal compression
6. Cover filter or relocate to frost-free storage if possible

⚠️ Critical: The FDB750’s substantial media bed retains significant water. Ensure complete drainage before freezing conditions. Ice expansion can crack the tank and void warranty.

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🪨 Filter Media Information

The Certikin FDB750’s exceptional media capacity and deep bed design are optimised for use with graded filter media, delivering maximum particle capture through the extended bed depth.

Recommended Media Configuration:

Layer	Media Type	Size	Purpose
Support Layer	Gravel	3.5mm	Supports sand bed, aids water distribution
Filtration Layer	Filter Sand	0.35-0.5mm	Primary filtration medium

Compatible Media Types:

Media Type	Filtration Rating	Lifespan	Benefits
Silica Sand	20-40 microns	5-7 years	Economical, proven performance
Glass Media	5-15 microns	10+ years	Finer filtration, longer life, eco-friendly
ZeoSand	3-5 microns	5 years	Superior clarity, reduced chemical demand

Media Capacity: 518kg total

💡 Professional Tip: The FDB750’s substantial 518kg media capacity represents a significant investment in filter media. Consider glass media for longer service life and finer filtration – the higher initial cost is offset by 10+ year lifespan versus 5-7 years for sand.

Signs Media Needs Replacing:

• Persistently cloudy water despite correct chemical balance
• Shortened filter cycles requiring frequent backwashing
• Visible media particles in pool returns
• Media channelling or clumping
• Inability to maintain pressure after backwash
• Increased chemical consumption without improved clarity

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✨ Filtration Performance

Metric	Value
Filtration Rating (Sand)	20-40 microns
Filtration Rating (Glass)	5-15 microns
Filter Area	0.44m²
Design Flow Rate	22m³/h
Deep Bed Advantage	Maximum contact time for superior particle capture

Micron Rating Guide:

Rating	What It Removes
40+ microns	Visible debris, leaves, 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, cloudiness
Below 5 microns	Near invisible particles, bacteria

FDB750 Performance Advantage:

The FDB750’s 0.44m² filtration area is the largest in the deep bed range – over 130% larger than the FDB500 and 47% larger than the FDB600. Combined with 518kg media capacity (85% more than FDB600), this flagship model delivers:

• Extended contact time for maximum particle capture
• Substantially longer backwash intervals
• Superior dirt holding capacity for busy pools
• Exceptional water clarity even under heavy use
• Reduced maintenance frequency throughout the season

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⚙️ Valve Positions & Functions

The included 6-way multiport valve provides complete control over all filtration and maintenance operations:

Position	Function	When to Use
Filter	Normal filtration mode	Daily operation – water flows through media and returns to pool
Backwash	Reverses flow to clean media	When pressure rises 0.5-0.7 bar above baseline
Rinse	Settles media after backwash	60-90 seconds after every backwash cycle
Waste	Bypasses filter, drains to waste	Vacuuming heavy debris, lowering water level
Recirculate	Bypasses filter, returns to pool	Distributing chemicals, troubleshooting
Closed	Stops all water flow	Maintenance, winterisation

⚠️ Important: Always switch off the pump before changing valve positions. The FDB750’s higher flow rate means valve operation under pressure can cause significant damage.

🎯 Ideal Applications

Application	Pool Size	Suitability
🏠 Large Residential In-Ground	100,000-176,000 L	✅ Excellent – ideal match
🏡 Premium Family Pools	80,000-130,000 L	✅ Excellent – superior performance
🏨 Holiday Let Properties	Up to 130,000 L	✅ Ideal – minimal maintenance
🏊 Large Above-Ground Pools	60,000-100,000 L	✅ Premium Choice
🧖 Commercial Swim Spas	20,000-40,000 L	✅ Excellent
🏢 Light Commercial	Up to 130,000 L	✅ Good – verify PWTAG compliance
🏫 Small School/Club Pools	Verify requirements	⚠️ Consult regulations

Recommended For:

• Large residential pools requiring exceptional water clarity
• High-traffic family pools with demanding filtration needs
• Holiday rental properties requiring reliable, low-maintenance filtration
• Pool owners upgrading from inadequate filtration systems
• Installations where extended backwash intervals are essential
• Pools in areas with heavy environmental debris loading
• Customers seeking the ultimate in deep bed filtration performance

💬 Frequently Asked Questions

Q: What size pool will this filter handle? A: The FDB750 is suitable for pools up to 176,000 litres with an 8-hour turnover, or optimally up to 132,000 litres with a 6-hour turnover. The powerful 22m³/h flow rate makes it the ideal choice for large residential and light commercial applications.

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. With 518kg media capacity, the FDB750 typically requires backwashing every 2-3 weeks during swimming season – significantly less often than smaller filters.

Q: What filter media should I use? A: The FDB750 is compatible with silica sand (0.35-0.5mm), glass media, or zeolite. Certikin recommends a graded bed using 3.5mm gravel as a support layer beneath the main filter sand. Total media capacity is 518kg.

Q: How much media do I need to purchase? A: The FDB750 requires 518kg of filter media. This typically comprises approximately 75-100kg of gravel support layer and 418-443kg of filter sand or alternative media.

Q: How long does filter media last? A: Silica sand typically lasts 5-7 years, while glass media can last 10+ years. Given the substantial media investment for the FDB750, glass media offers excellent long-term value despite higher initial cost.

Q: What pump do I need? A: Pair with a pump delivering between 15.0-22.0m³/h. Never exceed the filter’s maximum flow rate of 22m³/h. A 1.5hp to 2.0hp pump typically suits most installations. Ensure 2″ pipework throughout.

Q: Is the multiport valve included? A: Yes, the FDB750 comes complete with a side-mounted 6-way multiport valve with 2″ connections, pressure gauge, manual air vent, and manual water drain – ready for installation.

Q: Is this suitable for commercial use? A: The FDB750 can suit light commercial applications up to approximately 130,000 litres. For commercial pools, always verify compliance with PWTAG guidelines and local authority requirements. Heavy commercial use may require dedicated commercial filtration systems.

Q: How does it compare to the FDB500 and FDB600? A: The FDB750 offers 132% more flow rate than FDB500 (22 vs 9.5m³/h), 131% more filtration area (0.44 vs 0.19m²), and 166% more media capacity (518 vs 195kg). Compared to FDB600: 47% more flow rate, 47% more area, and 85% more media capacity.

Q: What warranty is included? A: Certikin products are backed by manufacturer warranty. Contact Parts4Tubs for full warranty terms and conditions applicable to your installation.

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📄 Downloads & Resources

📄 Technical Documentation – Contact Parts4Tubs for installation manuals and technical datasheets

📄 Certikin Product Literature – Available from certikin.co.uk

📄 Spare Parts Information – Full range of replacement parts available from Parts4Tubs

📄 Media Calculation Guide – Contact our team for media quantity advice

💡 For detailed installation instructions, media specifications, pump matching guidance, and troubleshooting support, please contact our technical team.

✅ Why Choose the Certikin FDB750

✅ Maximum Filtration Capacity – 0.44m² filtration area and 22m³/h flow rate handles the largest residential pools

✅ Exceptional Dirt Retention – 518kg media capacity delivers the longest backwash intervals in the range

✅ Superior Water Clarity – Deep bed design captures finer particles for consistently crystal-clear water

✅ Premium Build Quality – Bobbin-wound fibreglass construction from one of the UK’s most trusted manufacturers

✅ Complete Installation Package – Filter arrives with 2″ multiport valve, pressure gauge, and fittings pre-installed

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

✅ Light Commercial Capability – Suitable for small commercial applications where regulations permit

✅ Proven Reliability – Certikin has been the UK’s leading pool equipment supplier for over 50 years

✅ Long-Term Investment – The flagship model delivers professional-grade performance for years to come

✅ Reduced Running Costs – Extended maintenance intervals save time, water, and money

🛒 Why Buy From Parts4Tubs

✅ UK-Based Company – Local support and expertise you can rely on

✅ Fast UK Delivery – Quick despatch to get your pool up and running

✅ Expert Advice – Our team understands pool filtration and can help with sizing, pump matching, and installation queries

✅ Competitive Pricing – Great value on genuine Certikin equipment

✅ Full Warranty Support – We stand behind every product we sell

✅ Easy Returns – Hassle-free 30-day returns policy

✅ Complete Range – Filter media, spare parts, pumps, and accessories all available

✅ Trusted Supplier – Built on the success of buildahottub.com with years of industry experience

✅ Large Order Support – We can assist with media quantities and delivery logistics for the FDB750

🏊 Summary

The Certikin FDB750 Deep Bed Sand Filter is the flagship model in Certikin’s acclaimed deep bed range, delivering maximum filtration performance for large residential pools up to 176,000 litres. Featuring an impressive 750mm fibreglass tank, powerful 22m³/h flow rate, 0.44m² filtration area, and substantial 518kg media capacity, this filter provides uncompromising water clarity with significantly extended maintenance intervals. Complete with factory-fitted side-mount 6-way multiport valve, pressure gauge, and 2″ connections, the FDB750 arrives ready for installation on demanding pool systems. The definitive choice for pool owners seeking the ultimate in deep bed filtration technology, backed by Certikin’s 50+ years of UK-trusted quality.