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GUIDE / SWIMMING POOLS

Why change the sand in my filter?

How do you change the sand in a pool filter, anyway? Start by deciding what type of sand you will use. There are several options to choose from. Learn when it’s time to change it, so you don’t have to constantly struggle with dirty, murky water.

Pool filter sand?

The filter media is the material that holds these contaminants. In this case, sand is that media.

Sand is such an excellent filtration media that it is used in other water safety applications, such as wastewater treatment, septic systems and even drinking water.

To the untrained eye, most sands look very similar, and you might think that all sands are created equal, but that is not the case. Don’t be tempted by the cheap bag of play sand sitting in your garage. It will destroy your filtration system. Make sure you always use the right filter media!

Silica sand

The most commonly used pool filter sand is #20 silica sand. It comes from crushed quartz, which creates silica grains with jagged edges that are excellent for trapping passing water particles.

Silica sand is mined, not manufactured.

Recycled Glass Sand

If you are looking for a low environmental impact filter media, glass sand is an effective alternative to silica. Made from 100% recycled glass, it is smooth to the touch but retains particles.

The glass grains are all different sizes, which helps minimize channeling, which occurs when pool water works its way through the sand and passes through the filter virtually unfiltered. Glass sand also has a negative charge, which allows it to excel at capturing iron and manganese particles. This is especially useful if your pool is filled from a hard water source.

Why change your pool filter sand?

The pool pump pulls water into the filter, where it passes through the sand, where contaminants are trapped. The clean water returns to the pool. How does the sand trap harmful substances while allowing clean water to pass through?

Although they are far too small to be visible to the naked eye, both types of sand have a rough surface where contaminants are trapped as the water passes through.

Over time, the precipitating water wears away the pitted surface of the sand, leaving it smooth and round. When you look under a microscope at the sand on beaches with high waves, you see that it is noticeably smoother than the sand on quieter beaches. The same principle applies to the sand in pool filters, which has water flowing through it for several hours a day.

When pool filter sand is weathered, it doesn’t have serrated edges to catch and hold contaminants. Your pool may begin to look cloudy or require more frequent shock treatments as the filter media approaches the end of its life.

When to change the sand?

It has a rather short lifespan – three to five years only. During those few years, contaminants build up in the sand.

During the first couple of years, this actually improves the filtering ability of the sand, because in addition to the roughness of the sand, the contaminants that build up also act as a filter for the water that passes through the filter.

But eventually, all this extra dirt builds up so much that it makes the filter susceptible to clogging. At the same time, the weathering makes the sand unable to collect more contaminants. The efficiency of your filter decreases as well as the quality of your pool water.

Two other things can happen when your sand is no longer at its best. Pressure can build up inside your filter, as it becomes harder for water to pass through the clogged sand. The water will then seek out the path with the least resistance and channel through the sand, which may reduce the pressure a bit, but virtually eliminates filtration.

Why not just clean it with a backwash?

You must perform a backwash whenever the manometerpressure reaches 10 psi more than normal operating pressure. You can also perform a backwash if the water is a little cloudy, but the chemical composition is good.

The backwash flushes out sand and removes debris. It can be performed as part of your routine pool maintenance

If you want to give your sand a little extra cleaning, use a sand filter cleaner every year (Rapid Action Filter Cleanse). Think of this product as a sand degreaser. It helps remove oils and other contaminants that the backwash can’t get rid of.

Conclusion

Backwash and filter cleaner help improve water pressure and clarity, but sand eventually wears out and must be replaced. If your sand is in the three- to five-year range, and pressure and clarity are common problems, it’s probably time to replace it.

Feel free to come in and meet with one of our in-store technicians for assistance when it’s time for you to change your filter material in your filter.