Pool filtration systems: sand or cartridge?
Your filter is one of the most important parts of your swimming pool, working with your pool pump to keep the water clean and debris-free. To maintain a perfect level of cleanliness, Canada has by-laws regarding how often fresh water circulates through public pools; with this in mind, it’s important to research and invest in the getting the right system for your pool environment.
The information given here discusses sand filters and cartridge filters – two of the most common types. They each work differently, do a great job of keeping your pools clean, and have their own pros and cons.
So What’s the Difference Between Sand and Cartridge Filters?
Sand filters work using graded silica to trap dirt and debris that’s forced through the filter by the water pump. Sand filters are generally the lowest maintenance pool filters; if well maintained, sand filters can last up 10 years without needing to be replaced. However, its good practice to change the sand in your filter every 5-8 years.
Regular Maintenance Requirements
The sand in a sand filter doesn’t need replacing often, but that doesn’t mean they’re maintenance free. Sand filters need regular back-washing, which is where the water is reversed to flow backwards through the filter, cleaning out dirt and muck.
Several types of back-wash mechanisms exist:
- a push-pull valve (also called a slide valve), and
- a multi-port valve
Regardless of valve type, always remember to turn off the pump motor before starting a backwash procedure. When you’re done backwashing, ensure you read the pressure gauge. It’s time to back wash your filter again when the pressure gauge reads 8-10lbs.
You should backwash your sand filter once a month on average, but there are a few reasons when you to need to backwash more frequently:
- Sand channels: channels are holes and gaps which open up in the sand and allow water and dirt to flow straight through the filter.
- Hard water calcification: if you have hard water, parts of the sand may have calcified, forming solid lumps. Calcium deposits like these cause the filter to be less effective.
- Water balance: Your water may be out of balance, causing sand to clump up and block the filter.
- Filter size: your filter may be the wrong size for your pool. An undersized filter won’t filter properly and will be overworked, which could lead to failure.
Should You Use a Sand Filter?
Is a sand filter the right type of filter for your pool? Keep these points in mind when deciding:
- Sand filters are one of the most cost-effective pool filters
- They can remove dirt as small as 20-40 micron
- Sand filters are easy to use
- They are very low maintenance
- But, they don’t operate well if your pool has a low gallon-per-minute (GPM) capacity
Unlike sand filters, cartridge filters allow water to pass through a specially made cartridgethart traps particles on its surface. Cartridge filters have becoming more popular as they are small, energy efficient and save water. Cartridge filters don’t require back-washing procedures like sand filters do, meaning that homeowners don’t waste extra water and energy in maintenance.
In addition, the small size of cartridge filters allows them run on small pumps as they run with a lower flow rate, saving energy.
Unlike sand filters, cartridge filter maintenance is much higher. There’s no back-washing as noted above, but the filter needs to be removed frequently and manually cleaned. Ideally, it’s best practice to remove the filter after you’re finished using the pool, then let it soak overnight in a an approved cleaning solution. If you’re short of time, it can be soaked for around an hour then put back into the filter unit.
Hose off the filter thoroughly before soaking it; this will help remove dirt and debris. In ideal conditions, you should only need to clean the cartridge a few times per season.
Please note that it’s practically impossible to clean a cartridge filter completely, and over time, it will become less clean, and you’ll need to replace it approximately every 18-24 months.
Buying the right type of cartridge filter makes a difference to efficiency and maintenance. When purchasing your cartridge, look for:
- Sharp filter pleats: the sharper the pleats, the larger the filtration area.
- Quality replacement cartridges: always use a trusted manufacture of filter cartridges in your system
Should You Use a Cartridge Filter?
Is a cartridge filter the right type of filter for your pool? Keep these points in mind when deciding:
- Cartridge filters are more energy efficient than sand filters
- They reduce water and power consumption
- Cartridge filters don’t require backwashing, and less plumbing is involved
- They are ideal for pools with low GPM
- Cartridges have a large surface area, which can screen-out more dirt and debris than a sand filter
- They are more time consuming to clean
- They are more expensive to purchase than sand filters
- Filters use cartridges that need to be replaced approximately every 18-24 months
Sand or Cartridge; Which is Right for my Pool?
When choosing which pool filter type is the right one for your swimming pool, there are a few things that you need to take into account, so do your research:
- Sand filters can appear attractive as the are less expensive up front, but there are hidden costs as they require backwashing, which uses more water and energy. Back-washing also puts additional wear and tear on your pump motor.
- Cartridge filters are perfect for pools with low GPM (gallon-per-minute) capacity, use less water, take up less space, and use less energy. But they do require more maintenance in the way of filter cleaning, and you need replace the cartridge more frequently than the sand used in sand filters.