Is it Time to Change my Pool Filter Sand?
Discover the signs and reasons why it may be time to take on this big project
When you weighed the pros and cons of each kind of filter for your pool, sand was the choice for you –and why wouldn’t it be? It’s been efficient, inexpensive, low-maintenance and your pool has been looking great for the last few seasons. But you may have forgotten that one of the cons of a sand filtering system is that the sand needs to be changed every 3-5 years and that can be an involved and physically demanding project. So before you roll up your sleeves and get to work, let’s review some of the reasons why you might want to change your filter sand and some of the signs it might be time for change.
Why Change Your Pool Filter Sand?
All the experts and manufacturers say you need to change your filter sand every 3-5 years, but why? Over time, the rushing water wears away at the surface of the sand (this is also known as weathering). The jagged edges wear down and become smooth as the sand ages which means they can no longer trap debris particles and dirt. Your pool may start to look cloudy or require more frequent shock treatments. You may see actual dirt and debris simply flowing back into the pool as well.
Backwashing also impacts the sand in a few ways. Small amounts of sand can be lost during backwashing, and over many years’ time, can add up to a considerable loss. Also, with each backwashing the oily dirt, debris, dead algae, and other gummy residue are pushed deeper into the sand bed. This collection of contaminants over a few years makes the sand incapable of collecting more contaminants and the filter efficiency declines.
Over the years gummed-up sand with filtered contaminants will start to fuse together and become almost brick-like so the water can no longer flow through it. Pressure can build inside the filter as a result so the water may seek a path of least resistance and cut a channel through the sand. With channels now cut through the sand bed, no dirt or debris are collected as the water flows through the filter – the water just flows through the channels and back into the pool basically unfiltered!
Signs Your Filter Sand Might Need Changed
If you are in that 3-5 year range of time and not quite sure if it is time to change the filter sand just yet, take a look at these signs your filter sand might need changed to help you make your decision.
Backwashing the filter more frequently
A consistent regular loss of pressure after backwashing is a good sign you need new filter sand. Backwashing the filter stirs up the sand and the filter pressure should rise again. But if you have old sand, it will quickly become brick-like, the pressure will become low and the filter will no longer work as effectively as it should as the sand settles from the backwashing. You will see this drop in pressure probably happen after about half a day or a day after backwashing the filter and that is a big indicator the sand needs changed
Dirt or grime buildup in the bottom of the pool
This could indicate that channels have produced in the filter sand and the water is running straight through the channels without being filtered at all. Without any filtration happening, dirt and grime is bound to settle on the bottom of the pool.
Cloudy water
If the water is still cloudy after balancing the chemicals (and maybe adding flocculant or clarifier), running the system the proper length of time and having a normal bather load, the sand may not be filtering properly. This is a common indicator the sand needs changing.
Sand filters are the most common pool filter in America, and one of the easiest to operate. Although changing the filter sand is an involved process you can do-it-yourself. If you think it’s time to replace your filter sand, we have got you covered. Check out our selection of filter sand products and read our how-to change your filter sand guide.