How to Backwash an Intex Sand Filter (Fast Guide)

Backwashing is the core maintenance job on an Intex Krystal Clear sand filter, and it takes about ten minutes once you know the valve. Unlike a full-size pool filter, most Intex SX-series pumps do not have a pressure gauge to tell you when the sand bed is clogged, so you work off water flow and a simple weekly schedule instead. The good news is the process is genuinely beginner-friendly: the whole thing runs off a single 6-position valve on top of the pump, and the drain hose you need ships in the box. This guide walks through the Intex 6 way valve backwash step by step, explains what every valve setting does, and covers the Intex-specific quirks that trip people up.

The Intex 6-Position Valve Explained

Every Intex Krystal Clear sand filter is controlled by one multiport valve with six labeled positions. Understanding the Intex sand filter valve settings is most of the battle, because the actual backwash is just turning this handle in the right order.

The two positions that matter for cleaning are Backwash and Rinse. This is the same six-position layout you will see explained in our full pool filter valve settings guide, just built into the smaller Intex housing.

Step-by-Step Intex Sand Filter Backwash

Here is the full Intex pump backwash steps sequence. Move slowly and unplug the pump every single time before you touch the valve.

1. Unplug the pump at the wall or GFCI outlet and wait a few seconds for the water to stop moving.
2. Reconnect the drain hose to the waste outlet on the pump base, and run it away from the pool to a spot that can take dirty, chlorinated water.
3. Set the 6-way valve to Backwash by pressing the handle down and rotating it.
4. Plug the pump back in and run it for 1 to 2 minutes. Watch the sight glass or the end of the drain hose and stop once the water runs clear.
5. Unplug the pump, turn the valve to Rinse, plug it back in, and run 30 to 60 seconds.
6. Unplug once more, return the valve to Filter, and plug in to resume normal filtering.

The reason you always unplug before moving the handle: the valve seals against water pressure with a soft internal gasket, and rotating it while the pump is pushing water can shear that gasket or force a leak. This is the number-one cause of a leaking Intex valve, and it is completely avoidable. The general procedure is the same one covered in our master guide on how to backwash a sand filter, adapted to the plug-in Intex pump rather than a hard-wired one.

When to Backwash an Intex Sand Filter

Full-size pool filters tell you when to backwash with a pressure gauge that climbs 8 to 10 PSI over its clean baseline. Most Intex SX-series pumps do not include a gauge, so that trigger is not available to you. Instead, judge by two things: flow and schedule.

Flow is the reliable real-time signal. When the sand bed clogs, the return jets in your pool weaken and the water turns hazier. Weak return flow with a full pump basket almost always means the sand needs backwashing. As a baseline routine, backwash roughly once a week during swim season, and more often after a storm, heavy pollen, or a crowded pool day dumps extra debris into the water. Our guide on how often to backwash a pool filter explains why a rough schedule beats over-cleaning: a lightly loaded sand bed actually traps finer particles than freshly cleaned sand, so backwashing too early leaves your water cloudier.

Intex-Specific Quirks Worth Knowing

A few things set Intex gear apart from a standard above-ground sand filter, and knowing them saves confusion.

The built-in timer. Many Intex Krystal Clear pumps have a built-in digital timer so the pump cycles automatically. That timer controls run hours only. It does nothing for backwashing, which is always manual. Do not assume the timer keeps the sand clean.

Plunger-style valve on smaller models. The larger Intex sand filter pumps use the full rotating 6-way valve described above. Some of the smallest Krystal Clear units instead use a simpler plunger or slide valve with fewer positions. If your handle only pushes and pulls rather than rotating through six labels, you have the plunger type: pull up to backwash, push down to filter, and there is no separate Rinse position to run.

The drain hose. Intex backwashing relies on the flat drain hose that ships with the pump. It clamps to the waste outlet on the pump base. Keep it with the pump, because without it a Backwash cycle just sprays dirty water at your feet. Route it downhill toward a drain or absorbent ground, away from the pool and any plants that dislike chlorine.

For a walk-through of the whole Intex Krystal Clear backwash and initial setup together, our guide on how to set up an Intex pool pump and filter covers assembly, priming, and first-run priming order.

How Often and How Long

For a typical residential Intex pool in season, backwash about once a week and run each Backwash cycle for 1 to 2 minutes, stopping the moment the discharge runs clear. Running Backwash much longer than the clear point just wastes water and chlorinated pool water without cleaning further. Follow every Backwash with a 30 to 60 second Rinse. Two short cycles at the right time beat one long one.

If you are also topping off or replacing the sand, note that fill amount is model-specific and matters for clean filtering. Overfilling causes sand blowback and weak flow, so check the exact figure in our guide on how much sand for an Intex sand filter before you pour.

Troubleshooting

Weak flow after backwashing. If the return jets are still weak after a full backwash and rinse, first empty the pump strainer basket and clean the intake. If flow is still poor, the sand may be channeling or coated with body oils that reversed flow cannot lift. That points to a deeper clean or a sand change rather than another backwash.

Sand coming back into the pool. This is almost always a skipped or too-short Rinse cycle, so run Rinse a full 30 to 60 seconds every time. If it persists, you likely overfilled the tank or used the wrong grade. Use only 0.45 to 0.55mm pool-grade silica sand and confirm the fill amount for your model. A cracked internal lateral can also send sand back, which means opening the tank to inspect.

Valve leaking. A valve that weeps or sprays almost always means it was turned while the pump was running, which shears the internal gasket. Always unplug first. If the gasket is already damaged, Intex sells a replacement seal kit for the SX-series valve that swaps in without replacing the whole pump.

If you want the general theory behind all of this before your next clean, the broader walkthrough on how to backwash a pool filter fills in the why behind each step. And if your Intex pump did not come with a drain hose or the original wore out, a replacement intex sand filter pump kit or hose is an inexpensive fix.

Related Guides

• How to Backwash a Sand Filter - the master step-by-step procedure for any sand filter
• How to Backwash a Pool Filter - the general procedure for every filter type
• How Much Sand for an Intex Sand Filter - the model-by-model fill amounts
• How to Set Up an Intex Pool Pump and Filter - assembly, priming, and first run
• How Often to Backwash a Pool Filter - the right cleaning frequency
• Pool Filter Valve Settings Guide - what every multiport position does