Cartridge or Media Filter?
Introduction to filtration systems and filtration media.
Everyone wants a pool that’s dive-ready all year round. But it can be challenging when you get more than your share of leaves, heavy rain or swimmers. In fact, you probably spend more time cleaning, testing and balancing your pool than swimming in it (if you don’t have the right equipment to do the heavy lifting!).
But there’s a trick to minimising maintenance without cutting corners –switching to glass filter media. Not only can it improve your pool water’s clarity, but it can also reduce maintenance times, lower chemical costs and slash your energy bills.
Sounds awesome, right?
In this guide, we’ll cover everything you need to know about glass media, like what it is, how it can benefit your pool and the steps you can take to make the switch. Let’s plunge in!
Made from grains of recycled glass, glass filter media is used in media filters to keep debris and bacteria out of your pool. As water is pumped to the filter, it passes through the glass media, which captures particles using a static charge. The clean water is then syphoned back into the pool through the return jets.
In the past, media filters were considered less effective than cartridge filters or diatomaceous earth (DE) filters. This is because sand media wasn’t always a great performer. While it was affordable and readily available, it only filtered about 20–40 microns. This was less than DE filters, which could filter particles as small as 5 microns. In addition, sand could erode, clump or create channels of unfiltered water, reducing its effectiveness over time.
When glass media came on the scene in the 1990s, it matched DE’s filtration powers (without being as costly or high-maintenance) and pushed media filters back into the limelight. Since then, glass filtration has grown in popularity, not just because it works well, but also because it provides a range of benefits, not just for your pool, but also for your finances and the environment.
Whether you’ve just installed a new pool or you’ve had one for years, here are eight reasons why you should upgrade to glass filter media:
Unlike cartridge filters, which require monthly rinsing (or overnight soaking if they’re really dirty), glass media only requires backwashing every few months. This can take as little as five minutes, depending on the size of your pool. What’s more, glass media only needs to be replaced every 8–10 years, while cartridge filters need to be replaced every 2–3 years and sand media every 3–5 years. This means less monthly maintenance and more swimming!
Most media filters come with a 10-year warranty, which is longer than the lifespan of a standard cartridge filter (about 2 years). Glass media itself can last for 8–10 years because it’s made from recycled glass bottles. These are harder than standard glass and less prone to erosion. On the other hand, sand media breaks down after about 5 years. This means that media filters can last 5 times as long as cartridge filters, and glass media twice as long as sand!
Glass filter media can remove particles as small as 5 microns in size, which keeps your pool water healthier and clearer. By comparison, sand only filters about 20–40 microns and cartridge filters filter about 10 microns. (FYI: A speck of dust can be about 40 microns and unicellular green algae can be 5–10 microns.)
There are a couple of reasons why glass media can filter more effectively. First, glass doesn’t pack as densely as sand. In other words, it uses the entire depth of the filtration media, while sand only uses the top layer. This means that it traps more particles as water passes through.
Second, glass media has a negative charge that attracts particles more readily. This means it can trap 30 per cent more debris than conventional glass, keeping your pool cleaner.
Most glass media is made from durable recycled glass. Not only does this put less pressure on our natural resources, but it also reduces landfill. And because glass media lasts longer than sand or cartridges, you don’t have to replace it as frequently, making it an eco-friendly choice for your pool.
Compared to sand filters, which require backwashing every 1–2 weeks, or cartridge filters, which need to be cleaned monthly, glass media only needs to be backwashed every 2–3 months. The duration of the backwash is also shorter because glass is smooth and allows the easy passage of water. What’s more, if you have Viron Active Glass Media, which uses up to 50 per cent less water than sand during backwashing (see table below), you could save even more water.
Glass media is less permeable than sand, which means that debris like suntan lotion or bacteria can’t get ingrained. Instead, glass holds onto the debris with a static charge. This allows it to come off easily during backwashing. No residue left behind! Sand grains, on the other hand, are porous, making them a breeding ground for bacteria – particularly if you don’t backwash them often enough.
While there’s a higher upfront cost with glass media, you don’t have to replace glass or backwash it as often as sand. The backwash also happens at a lower speed, which reduces energy consumption. And because glass media keeps your pool cleaner, you won’t need as many chemicals to keep your water balanced, nor will you have to run your automatic pool cleaner as often. This can save you hundreds of dollars in water, energy and chemical costs every year!
Mineral pools perform best with glass media filtration, so if you’re already using glass media and planning to convert to a mineral pool, you can do this with minimal effort or expense. All you need is a chlorinator (if you don’t already have one) and minerals!
Switching from sand to glass filter media is pretty straightforward but it does requires a bit of work. It’s actually not that different to replacing sand or zeolite in your pool filter. In case you’re up for a challenge – here’s our step-by-step guide:
WHAT YOU’LL NEED
Screwdriver (if needed)
Large scoop or pool filter sand extractor
Gaffer tape or plastic bag with elastic
Mask and protective glasses
Step 1: Turn off the filter
Turn off the filter and pump. If the pump kicks in while you’re changing the media (this can happen if it’s on a timer), it could damage your equipment.
Step 2: Drain the filter tank
Turn the drain cap gently to release the air, then remove it completely to let the water drain out. If you don’t want the water to spill on the ground, attach a hose over the drain or place a shallow basin underneath it.
Step 3: Remove the multiport valve
Remove the pipes or hoses attached to your multiport valve. Once you’ve done this, remove the multiport valve itself. If it’s screwed in place, unscrew the bolts with a screwdriver and lift the valve off the pipe.
Step 4: Cover the standpipe
Inside the tank is an open standpipe with laterals (or arms) branching out at the bottom. Cover the top of the standpipe with gaffer tape (or plastic secured with an elastic band) to prevent any media from getting inside and clouding your pool water.
Step 5: Remove the sand
Remove the sand from inside the tank. You can do this by scooping it out into a wheelbarrow or using a pool filter sand extractor. The second option is faster and cleaner – and much like using a large syringe!
Step 6: Rinse the tank
Once the sand has been removed, remove the standpipe and give it a rinse. Clean out the tank with a garden hose. The remaining sand should come out of the exit drain at the bottom. Put the standpipe back inside the tank.
Step 7: Check the tank
Inspect the filter for any damage or cracks. Patch these as necessary or replace the filter if it’s at the end of its life.
Step 8: Half-fill the filter tank with water
Replace the drain plug and half-fill your filter tank with water. This will cushion the glass media and protect the laterals as you’re pouring it in.
Step 9: Add the glass media
Using a mask and protective glasses, pour the glass filter media into the tank. Follow the instructions on the packet to determine the right amount for your filter. Pour the media slowly so it doesn’t spill outside of the tank. As a rule, coarse grain should go in the bottom followed by finer grain on top. Spread it out as you go so it fills the tank evenly.
Step 10: Fill the tank with water
Fill the tank with water, remove the covering on the standpipe and replace the multiport valve. Reattach your pipes or hoses, making sure they’re secured tightly.
Step 11: Backwash the filter
Turn on the pump and backwash the filter to remove any sand. Do this for a couple of minutes until the water runs clear.
Step 12: Rinse the filter
Turn off the pump, set the multiport valve to rinse and turn the pump back on. Rinse the filter for a minute or so.
Step 13: Turn on the filter
Turn on the filter (normal operation mode) and check for leaks. If you see any, tighten your pipes or hoses.
Step 14: Check the pressure gauge
Check the pressure gauge and make a note of the number in your pool diary. When it’s 10 PSI (pounds per square inch) above this number, it’s time for your next backwash.
If you’ve got a cartridge filter, changing to a media filter isn’t too difficult. It just involves a few extra steps. First, choose a media filter for your pool size and pool pump flow rate. If you’re not sure which one is right for you, consult a pool professional for advice. A wrongly sized media filter (or any filter, for that matter) can result in poor filtration!
Once you’ve got the media filter, it’s time to instal it. First, disconnect and remove the cartridge filter and put the media filter in its place. Next, reroute the pipes to the inlet and outlet. If you don’t know how to do this, consult a pool technician or plumber.
Once the pipes have been rerouted, add the standpipe and laterals into the tank, then follow Steps 9 to 13 above. Your new glass media filter is ready to go!
Choosing the right pool filter is one of the most important decisions you’ll ever make for your pool, right behind choosing the right pool pump or automatic cleaner. But sometimes your filter lets you down, either because the sand isn’t keeping your pool clean enough, or you’re tired of washing your cartridge filters every two weeks.
If that’s the case, upgrading to glass filter media could be the answer. Not only can it improve the clarity of your pool water, but it can also reduce pool maintenance and minimise backwashing time. This means fewer chemicals, less cleaning and lower monthly bills. That’s a win-win-win in our books!