Cartridge Filters vs Sand Filters
Let’s talk about filtration and keep your pool water clean and healthy!
Swimming pool filters are the key feature in keeping your pool water healthy and bacteria free, allowing you and your family the peace of mind that your pool water is not hiding any nasties that are going to make you sick. While chlorine and other sanitizers work by killing the bacteria, the filter is what removes them from the water, so it’s important to have an optimal working filter at all times. But which one is best for your new swimming pool?
As leading pool builders Gold Coast has on offer we get this question more often than not, so let’s work through it so you can make an informed decision pre concrete pool construction.
A number of considerations
Before you choose what type of filtration you are going to have on your new concrete swimming pool, you first need to consider some key points. The size of your swimming pool, how much money you want to spend on the initial filtration set up, and on things like replacement items, how much cleaning and maintenance you are willing to do, as well as if you have access to plumbing for backwashing your filter. So, which one is right for you? Cartridge, sand or glass?
What’s best? Cartridge or Sand Filters?
We will break down the age-old debate of cartridge filters vs sand filters,
Starting with sand filters.
A sand filter consists of a large dome, that is approximately half filled with sand. Water is pushed down through the sand from your pool’s filtration pumps, it captures dirt, debris and other harmful bacteria on the way through, water is then pumped back into your swimming pool from the top of the filter through a return pipe.
The sand used in filtration is round and of various sizes and grades. When placed under a microscope it shows small cracks and imperfections along the surface. These cracks catch the microns (bacteria) and debris as they pass through, however some smaller microns may not be captured in a sand filter. Sand filters can filter down to approx. 20 microns – this means you need to carefully manage your swimming pool chemicals, in order to maintain your pool health.
When the time comes to clean the sand, your pool pump pressure gauge will change as an indication that backwashing needs to occur – backwashing is the process that cleans the sand – it’s relatively easy in terms of cleaning. To backwash a sand filter, you reverse the flow of water through the filter to stir up the sand and flush out the build-up of bio foul and contaminants through a dedicated backwash pipe.
A sand filter is relatively inexpensive in terms of maintenance, the sand only needs to be replaced every 5-7 years, however you will lose some water when backwashing, so your pool water and chemicals will need to be adjusted each time after your backwash.
If your beautiful new concrete swimming pool has a ‘cloudy’ appearance to it at night-time, this is fairly common for a sand filter – the particles floating in your pool are tiny particles of sand dust that cannot be collected during the filtration process – unfortunately it’s unavoidable with a sand filter.
Better filtration sometimes means more money and maintenance.
Cartridge filtration is next on the list of option – its less bulky than a sand or glass filter, it has the ability to filter a larger water ‘area’ due to the structure of the wide and deep pleats in the heavy-duty polyester filter fabric. If you do not have access to a storm water drain near your swimming pool, cartridge filtration will become your only option for a pool filter.
A cartridge filter will catch more fine debris than a sand filter and will filter down to approximately 10 microns (half the size of a sand filter)
While a cartridge filter will catch smaller particles, it also requires more maintenance – depending on your pool usage, you will need to remove and clean the cartridge every 1-3 months – this can be done with the use of the garden hose. At least once per year you should consider removing the filter and soaking it overnight in a filter cleaner to remove the harmful bacteria build up. You will also need to replace the cartridge every 1-2 years, depending on your swimming pool location and use.
Glass – the crem de la crop
Similar to sand filters, glass filters use the same large dome housing, the only difference is the product used inside the filter – glass is a great option for concrete swimming pool filtration – not only does it filter down to between 5 to 10 microns (even better than cartridge filters), but the recycled, heat-treated glass chips used in glass filtration have a uniform surface. They don’t have cracks and flaws along the edges for fine debris and particles to ‘hide’ in. Therefore, they tend to be a premium filter option.
When your glass filter is backwashed, it takes less time as the glass is lighter than sand so therefore you lose less water and chemicals from your pool during the cleaning process. The glass inside the filter also lasts up to 3 times longer than sand due to the advanced heat treatment process.
Glass filters are fairly hassle free and won’t leave a cloudy look in your pool like a sand filter can and the bonus is that if you already have a sand filter, you can swap it out for glass, relatively effortlessly. Ask your local pool shop for assistance or advice on this.
Backwashing and local laws
And we’re not talking about the idea of not wanting your water back after your 2-year-old has had a drink (yikes).
Some councils may have regulations around the disposal of pool backwashing water. Due to the salt and or chemicals in your pool water, some local councils will not allow this to be washed into local waterways – because of this, you may not have a choice of sand or glass. In these instances, you only have the cartridge filter available to you as this type of filter can be cleaned under fresh running water onto the garden or down into the household plumbing. It’s worth looking into your local council regulations, prior to making your filtration choice for your new swimming pool.
Filtration Equipment Cover / Box
Did you know you can conceal your swimming pool with a filtration box? That’s right! Hide it away, and maintain the beauty of your space.
In need of a quote for your next concrete pool project?
Considering a new concrete swimming pool in your backyard? Contact the friendly team at Gold Coast’s multi award winning Bali Pools today 07 5576 0900 and ask us to include a glass filter as part of your swimming pool quote.