Why is my pool filter blowing out sand when backwashing?

Author: Dr. Desmond Cronin PhD  |  Last update: Sunday, June 19, 2022

Sand coming from the pool filter is the sign of a broken component in the filter. If your pool has a sand filter, it goes without saying that the sand should stay in the filter. If you see it blowing out into the pool, something is broken.

Is sand supposed to come out during backwash?

Often, excess sand gets into the wrong places when refilling and will sand to come out into the pool or out of the backwash hose. But it should go away after a few runs. In general, you shouldn't be losing sand from your sand filter. Nor should any sand be coming out during backwashing, rinsing or filtering.

Why does sand come out of my filter when I backwash?

Your pump may be too large or the sand level too high in the filter. When the filter is backwashing the water flow can cause the sand to rise high enough and overflow into the standpipe, which will allow the sand back into the pool.

Why is my pool filter spitting out sand?

If you believe the sand is from your filter, then the most likely problem with your sand filter is a cracked lateral. Laterals are tubes at the bottom of your filter (you can see them here). Water filters through the sand and is collected by these laterals and then shot through standing pipe and back into your pool.

How do you get sand out of a sand filter?

How to Change the Sand
  1. Get the Right Equipment. Be sure you have everything you need on hand before you begin the process. ...
  2. Turn the Power Off. ...
  3. Drain the Tank. ...
  4. Remove the Multiport Valve. ...
  5. Remove the Old Sand. ...
  6. Withdraw the Lateral Assembly and Pipe. ...
  7. Wash the Tank. ...
  8. Replace the Lateral Assembly and Pipe.

Q&A: what causes sand to Blowback into the pool after vacuum backwash and rinse?

Can you backwash a sand filter too much?

Can You Backwash Too Much? If you backwash your pool too much i.e. time duration and/or close frequency then yes you can cause a lot of problems. Some problems that can arise from backwashing your sand pool filter too much are: Loss of water – 500+ litres of water can be lost in each backwashing cycle.

Can you put too much sand in a sand filter?

Too much sand and your filter will likely not run correctly or may break when reassembling. Too little sand and you will have cloudy water no matter how much your filter runs.

How often should I backwash sand filter?

How Often Should You Backwash a Pool Sand Filter? As a general rule of thumb, you should backwash and rinse your filter about once a fortnight. The optimal time is right after you vacuum the pool. However, if your pool has had a lot more use than normal, it may be necessary to backwash once a week.

How much sand should I put in my sand filter?

How Much Sand to Add to Pool Filters? Sand filters are not filled completely full of sand, but only about 2/3 full, to allow “Freeboard” space in the tank, above the sand bed.

How do I know when to add sand to my pool filter?

The sand in your pool filter needs replacing every three to five years, sometimes even longer if your pool remains in relatively good condition when it's open. If you run your pool filter often all year and have a heavy bather load, the sand may need replacing sooner than three years.

How long should I backwash my sand filter?

After the hose fills with water, backwash your sand filter for 2 - 3 minutes, or until water runs clear.

At what PSI should I backwash?

In most high-rate sand filters, it's time to backwash when the pressure differential reaches 18 to 20 psi. But if the system has only an inlet pressure gauge, you should backwash when the pressure increases by 8- to 10 psi from initial post-backwash readings.

Can I use play sand in my pool filter?

It is not advisable to use play sand in your pool filter. The larger particle size and different chemical compositions of play sand mean that much of the dirt and debris in your pool water will just pass through the filter. It just isn't very effective at cleaning your pool water.

How much does pool filter sand cost?

Replacement sand for your sand filter typically costs around $25 per 50-pound bag, and your filter may require 100 to 600 pounds or more depending on the size and model. More than likely, you'll need about 350 pounds of sand for an average-sized inground pool filter.

What should the pool filter pressure gauge read?

Generally speaking, a pressure reading between 10 – 25 psi can be considered normal. Once you have installed a new filter, turn everything on and take a baseline reading. Each time that you change your pool filter take a new baseline reading.

How long do you rinse after backwashing a pool?

Turn the lever to RINSE, start the pump and rinse for about 15-30 seconds. Stop the pump and turn the lever to FILTER. This is the normal operating position. Close the drain outlet valve and start the pump.

Should I add DE to my sand filter?

DE particles are microscopic and have many sharp edges, trapping fine dirt particles that would otherwise be able to get through the sand. Small amounts of DE can be added to a sand filter after each backwash to improve the filtering.

What happens if you overfill a sand filter?

TOO MUCH SAND IN TANK - If you have too much sand in your filter tank, your backwash and rinse cycles will not be as effective. Leave at least 6" of space between the top of the sand and the top of the filter tank.

What PSI should my sand filter be at?

Your filter may be clean and normal at 9-10 psi, but your neighbor's filter gauge could run higher, and be clean at 15-16 psi. Some systems with very low resistance can run very low pressures, barely registering, while other filter systems can run quite high, pushing 30 psi when the filter becomes dirty.

Can you backwash too long?

Why will the sand last less if I backwash too often? Backwashing a filter too frequently will keep the sand so free of dirt buildup that it will not have the ability to remove the smaller particles of dirt and they will simply pass through sometimes causing cloudiness in water.

What pressure should you backwash a sand filter?

Typically, you should backwash a pool if the pressure gauge on your filter is at 8-10PSI at the starting level.

Can pool filter sand be used in sandbox?

Because play sand, also known as sandbox sand, is less expensive than pool sand, pool owners are often tempted to try using it in the pool filter. Play sand and pool sand are not the same, however, and are not interchangeable.

How do I know if my sand filter is bad?

How to Tell If Your Sand Filter Is Bad: 7 Common Pool Filter...
  1. A Slow Sand Filter. If your swimming pool begins to seem a bit cloudy or unclear, then you may have a sand filter that's running slowly. ...
  2. Leaking Multiport Valves. ...
  3. Broken or Bad Laterals. ...
  4. Dirty Sand Filter. ...
  5. Valve Failure. ...
  6. Tank Failure. ...
  7. Pressure Issues.

Is it better to run a pool pump at night or day?

It's best to run your pool pump during the day

Not only does sunlight give fuel for algae to grow, it also destroys your pool chlorine and this is why you should always run your pool during the day!

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