How to backwash a sand filter
Updated: 16.10.2026
You already own the pump, the pool looks dull, and you are about to move the valve. Sand in the water afterwards is usually a sequence error: the handle turned while the pump ran, or rinse was skipped on a valve that has it. This is how to backwash a sand filter on the above-ground units in this set, from the Products Compared editorial team on 16 October 2026, using the Intex manual, a related Bestway manual, and the listing text. It is not a price list. The [sand filter comparison](/hub/pool-care/sand-filter) is the table if you are still choosing. There is no lab test and no chlorine dose here.
You already own the pump, the pool looks dull, and you are about to move the valve.
You already own the pump, the pool looks dull, and you are about to move the valve. Sand in the water afterwards is usually a sequence error: the handle turned while the pump ran, or rinse was skipped on a valve that has it. This is how to backwash a sand filter on the above-ground units in this set, from the Products Compared editorial team on 16 October 2026, using the Intex manual, a related Bestway manual, and the listing text. It is not a price list. The sand filter comparison is the table if you are still choosing. There is no lab test and no chlorine dose here.
Our top picks
| Badge | Product | Valve | Media load | Mains | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  Intex Intex 26648BS | Not stated in the listing | Not stated | 220–240 V in the title | 9.2 | about £194.49 | View offer |
| Alternative |  AQUASTRONG AQUASTRONG SFPV120T | 6-way, stop pump before switching | 50 lb sand or 1.5 lb filter balls | ac; volts not stated | 8.8 | about £231.63 | View offer |
| Preis-Tipp |  Intex Intex SX925 26642BS | Title says 6-way; bullets say four functions | 6.5 kg silica, not included | Not stated | 8.2 | about £109.99 | View offer |
On this page
Fill the tank before the first run
Fit the centre pipe before any sand goes in. Sand down that pipe reaches the pool, and a backwash will not pull it out. Intex specifies No. 20 silica at 0.45–0.85 mm. Do not substitute a public-pool 16/30 grade because the bag says pool sand. Use the weight your own listing prints.
Keep the sand between the minimum and maximum lines, and keep the tank level. A Bestway Flowclear manual for the 58401E, not the model on these Bestway rows, says sand reaches the pool if the valve moves while the pump runs or the sand sits above the max line. Intex says the first backwash runs until the waste is clear, about three minutes. Pump off before the handle moves. Sand weights are on the sand filter pump buying guide.
Backwash, rinse, filter
Turn the pump off, then move the handle, every time, including between backwash and rinse. The SPSG100, the AQUASTRONG, and the SPSG130T print “STOP PUMP BEFORE SWITCHING VALVE POSITION” and list rinse. Bestway’s rows also list rinse. Match your handle, not another brand’s diagram.
Set backwash with the pump off, run until the waste is clear, then switch off. If the handle has rinse, clear the lines, switch off, and return to filter. If you have no gauge, use clear waste water, not a guessed pressure. The 26642BS bullets do not name rinse, though the title says 6-way. Do not invent a stop the card lacks.
If sand comes back
Usual causes are sand finer than 0.45–0.85 mm, sand above the max line, a tank off level, a handle moved while the pump ran, or a skipped rinse. Repeat the sequence first: pump off, backwash until clear, pump off, rinse if you have it, pump off, filter.
If the waste never clears, the grade may be wrong. Intex states a sand change at about four to five years, or two to three if you backwash often. That interval is Intex’s. If grit keeps returning after every move was made with the pump off, stop. Do not run a 120 V unit on a travel adaptor. Mains are on the pool sand filter UK plug page.
When to stop
A pump that will not start is not a valve position. Do not open the motor. UK reviews include pumps that died, and another backwash will not revive them. A burning smell, or an RCD that trips as the pump starts, means unplug if you can do so safely and call a qualified electrician.
HSG179 does not apply to a private pool used only by the owner, family, and guests. It can apply to a holiday let. If you are still unsure sand was the right swap, that fork is the sand filter or cartridge filter page. If you will not send water to waste, do not force this sequence.
Common questions
Do I turn the pump off before I move the handle?
Yes, every time, including between backwash and rinse. Three listings print “STOP PUMP BEFORE SWITCHING VALVE POSITION”. A Bestway 58401E manual, not the model on these Bestway rows, gives the same failure: sand in the pool if the valve moves while the pump runs. Let the pump stop, then move the handle.
What order is backwash, rinse, filter?
Pump off, backwash until the waste runs clear, pump off, rinse if the handle has it, pump off, then filter. Hayward describes rinse as the step that clears the lines. That is Hayward’s account, not a part on these pumps. If the card has no rinse, do not invent one. Return from a clear backwash to filter with the pump off.
Why is there sand in the pool after a backwash?
Typical causes are sand finer than 0.45–0.85 mm, a high sand level, a tank off level, a handle moved while the pump ran, or a skipped rinse. UK reviews on the small Intex units report this, including a 120 V unit said to have no rinse. If the sequence and the grade are right and grit still returns, stop. Do not open the laterals from this page.
How long is the first backwash on new sand?
Intex says until the waste is clear, about three minutes. That is its instruction, not a legal time for every small tank. If the water is still cloudy, keep going, and stop the pump whenever you move the handle. Then rinse only if your valve has that position. Do not copy a public-pool minimum onto a garden tank.
How often do I change the sand?
Intex states about four to five years in normal use, or two to three if you backwash often. Backwashing cleans the bed. It does not make the sand permanent. When you change it, refill with the grade and weight your model asks for, pipe first, then a first backwash until the waste is clear.
The pump will not start. What now?
Stop. A dead motor is not a backwash fault, and failed-pump reviews are not fixed by another valve position. Do not open the housing. A burning smell or a tripping RCD means unplug, if you can do that safely, and call a qualified electrician. If the pool is a holiday let, HSG179 may apply, and this sequence is not that guidance.
Related pages
Sources
Public UK sources and the Intex manual, checked on 16 October 2026. Shelf prices, stars and review counts are the amazon.co.uk figures for these eight listings.
- HSE: swimming pool safety (retrieved 16 October 2026)
- HSG179: managing health and safety in swimming pools (retrieved 16 October 2026)
- PWTAG: filtration rate calculator (retrieved 16 October 2026)
- PWTAG TN50: swimming pool filter specification (retrieved 16 October 2026)
- BS EN 16713-1:2016 domestic swimming pool filtration (retrieved 16 October 2026)
- Electrical Equipment (Safety) Regulations 2016, regulation 35 (retrieved 16 October 2026)
- Intex Krystal Clear sand filter pump manual (retrieved 16 October 2026)
- Electrical Safety First: plugs and fuses (retrieved 16 October 2026)