Residential Sand Filters for Swimming Pools

Sand filters for home swimming pools, 20 to 42 inch, 10 to 43.5 m3/h, filament-wound FRP with a 6-way valve. Made in Egypt, supplied without sand.

How a pool sand filter works

A sand filter pushes pool water down through a bed of graded silica sand: dirt stays in the bed and clean water leaves through the collector arms (laterals) at the bottom of the vessel, back to the pool. As the bed loads, the pressure on the gauge rises; a backwash through the 6-way multiport valve reverses the flow and sends the trapped dirt to waste. The six valve positions are filter, backwash, rinse, waste, recirculate and closed.

The five sizes and what each one passes

The residential range is top-mount, with the multiport valve on the lid, which keeps the footprint tight in a domestic plant room. Five vessels cover the range: T500-20 at 500 mm diameter with 0.20 m² of filter area and 10 m³/h rated flow; T600-24 at 600 mm with 0.28 m² and 14 m³/h; T750-30a at 750 mm with 0.44 m² and 22 m³/h; T900-36 at 900 mm with 0.64 m² and 32 m³/h; and T1005-42 at 1050 mm with 0.87 m² and 43.5 m³/h.

All five shells are filament-wound FRP. The 20, 24 and 30 inch vessels take a 6-way top-mount multiport valve; the 36 and 42 inch vessels take the 2 inch 6-way valve, matched to the larger pipework those flows require.

Filtration rate, and why the next size up is the cheap upgrade

Every vessel in the range is rated at a filtration rate of 50 m³/h per m² of bed area. That is the maximum, not a target. The rated flow of each filter is simply its area multiplied by that figure, which is why the numbers above scale the way they do.

Running below the maximum is what buys water clarity. At a lower velocity the bed traps finer particles, the pressure rise across it is slower and backwash intervals stretch out. Specifying one size larger than the minimum the turnover calculation demands is usually the least expensive quality improvement available on a residential pool, because the pump, the pipework and the running cost do not change.

Media: supplied empty, sand ordered separately

Our filters are supplied empty. The sand is a separate order, and the quantity is not something to estimate on delivery day — a bed that is short runs channels, and water finds the path of least resistance straight through to the laterals without being filtered. The charge for each size is: 20" 100 kg (4 × 25 kg bags), 24" 175 kg (7 bags), 30" 300 kg (12 bags), 36" 525 kg (21 bags).

The grade is 0.4–0.8 mm silica sand on every size. Up to and including the 36" that is the whole charge — the sand sits directly on the collector arms and no support layer is used. The 42" is the first size in the range that needs a 1–2 mm silica gravel underbed beneath the sand, because the vessel is deep enough for the sand to load the laterals unevenly without one. Its charge is 950 kg of sand (38 bags) on 300 kg of 1–2 mm gravel (12 bags).

Do not substitute a coarser sand for the gravel. 0.8–1.2 mm silica sand is a filtering grade, not a support grade, and it will not do the job the underbed is there for. Order the media with the filter and it arrives together.

Sizing a sand filter from turnover

Size the filter from turnover time, not from the surface area of the pool. Divide the pool volume by the target turnover — commonly six to eight hours on a private pool — to get the circulation flow the system has to carry, then pick the vessel whose rated flow comfortably exceeds it.

On that basis, at a six to eight hour turnover, T500-20 suits pools up to roughly 60–80 m³, T600-24 up to roughly 84–112 m³, T750-30a up to roughly 132–176 m³, T900-36 up to roughly 192–256 m³ and T1005-42 up to roughly 261–348 m³. Treat these as a starting point: pipe diameter, suction lift and the number of skimmers all move the answer. Send us the pool dimensions and the plant room layout and our engineers will confirm the filter and the pump together.

Sand filters for dealers, contractors and export

Waterstar has manufactured pool equipment in its own factory in Badr City, Cairo, since 1993, and exports to 14 countries. Every component of every filter is available as a spare part, from the multiport valve down to the laterals, so a filter is repaired rather than replaced. For a project, send the pool volume, the turnover you want and the plant-room layout; our engineers will confirm the filter, the pump and the media order together.