Top 5 Best Pool Sand Filters in 2019

Diatomaceous earth filters are expensive. Many municipalities strictly enforce DE disposal, and they aren’t the best fit for above-ground swimming pools. Cartridge filters only last a couple of years, and they can be tedious to clean. Is there an alternative to DE and cartridge filters?

pool sand filters

If minimal maintenance and low cost are your top priorities, a sand filter fits both of your requirements. Sand filters work well with in-ground and above-ground swimming pools, particularly large ones. Although the sand remains effective longer than diatomaceous earth, you have the option of replacing the sand with materials that have a smaller volume and filtration rate.

These filters consist of a tank with high-quality sand at two-thirds capacity. On the top or the side of the tank, there is a multiport valve next to the pressure gauge, which gives you access to the filter’s multiple settings. As water flows into the tank, the rough edges of the sand catch the debris in the water.

No matter the ground level or size of your pool, you’ll find a great sand filter in our review list. We’ve compiled a list of the most solidly constructed sand filters available. In addition, we added a buyer’s guide, which explains how to size the filter, what each multiport setting means and how to backwash your sand filter.

Best Pool Sand Filters

Pool Sand Filter Buying Guide

If you want to know more about how sand filters compare to diatomaceous earth and cartridge filters, check out our buyer’s guide, which also gives you the lowdown on the capabilities of silica sand and its alternatives. You’ll also find out how to size a sand filter according to your pool’s pump and volume.

Best Pool Sand Filters

Once you’ve found the right sand filter, our guide will tell you how to take care of it. In this guide, you’ll find instructions on how to replace the sand and backwash the filter. If you’re curious about your filter’s other settings, we’ve provided simple explanations that remove the mystery behind the multiport valve.

Filter Types: DE vs. Cartridge vs. Sand

Diatomaceous earth filters boast a 5-micron filtration rate, and you don’t need to break out chemicals to clean them. However, DE is pricey, and the filter’s grids only last 3 years. Most DE filters are incompatible with above-ground pools, and your city or county may have strict disposal rules for diatomaceous earth.

Cartridge filters can filter particles as small as 10 microns. You’ll use less water to clean them, and they work well with variable-speed pumps. Compared to sand filters, cartridge filters require more maintenance, and their lifespan is just as short as that of DE filters.

In terms of price and maintenance, sand filters are the winner. They also last much longer than DE and cartridge filters – often up to 7 years. However, there is one big downside to sand filters. They can only filter particles 20 microns and larger.

Characteristics of Sand and Its Alternatives

The type of sand used in sand filters is grade-20 silica sand. Many people prefer silica sand because it’s the cheapest medium, and it’s the easiest to maintain. Those who want a performance boost from their sand filter often opt for ZeoSand. Only half the amount of ZeoSand is needed, and it’s efficient at preventing chloramine buildup.

swimming pool filters sand

Made of recycled glass, crushed filter glass can trap particles as tiny as 2 microns. Filter glass also lasts much longer than silica sand, and you only need 20 percent the amount compared to silica. Pollyballs (polyester balls) have a 5-micron filtration rate. They’re resistant to chemical corrosion, and they can increase the pool’s flow rate by almost half.

Sizing a Sand Filter

There are two factors to take into account when choosing an appropriately sized sand filter – the pool’s pump and the pool’s capacity. When the size of the filter doesn’t match that of the pump, the system’s water flow will be hindered, and you could damage the filter.

For a 0.75 HP pump, you’ll need 2.7 square feet of sand. For a 2 HP pump, 5.8 square feet is appropriate. If the pool pump’s horsepower is rated at 1 or 1.5, you’ll need a filter that can hold 3.4 to 4.3 square feet’ worth of silica sand.

Sand filters are also sized by their flow rate of gallons-per-minute. The gallons per minute should meet or exceed that of the pool’s pump. At the very least, you’ll need 1 square foot of silica sand per 10,000 gallons of water. It’s perfectly fine to size the filter slightly bigger than the pump.

Cleaning a Sand Filter: Backwashing

The particles caught in between the sand granules gradually decrease the flow rate. Every 1 to 3 months, you’ll need to backwash your sand filter. You’ll know it’s time to take care of this routine maintenance task when the pressure gauge on the tank reads about 10 psi higher than normal.

swim pool sand filters

First, turn off the pump and the heater. Then, open the drain outlet, set the sand filter’s valve to backwash and turn on the pump. Let the filter run for a few minutes. Once the water appears clear, turn off the pump and set the valve back to filter. Now, you can turn on the pump and heater.

Multiport Valve Settings

Slide valves only have two settings – filter and backwash. The filter setting is the one that keeps the water clean and circulating, so you’ll use this setting the most. Backwash reverses the water flow, allowing you to clean the filter itself. Multiport valves have more settings, including rinse, waste, closed, recirculate and winterize.

Rinse flushes the tank after you replace the sand. Waste bypasses the filter when you vacuum. Closed halts the water flow, making it easier to repair a malfunctioning pump. Recirculate also bypasses the pump, and you’d use this if your filter is leaking or cracked. Winterize is suitable for closing down the pool at the end of swim season.

Replacing the Sand in Your Filter

To get as many working years as possible from the sand in your filter, we recommend decalcifying the sand by using a cleaner once a year. Once you notice that pressure increases are happening faster than usual, a cleaner won’t cut it – You’ll need to replace the sand.

swimming pool sand filters

Pull the tank’s drain plug and remove the filter’s dome. Then, disconnect the pipe and detach the filter valve. Taking care not to break the filter’s laterals and standpipe, scoop or vacuum out the sand. Once you remove the sand, flip over the tank and rinse the laterals with a hose.

Now, you can add new sand. Make sure to pour in enough water to prevent the laterals from cracking, and never add more sand than the filter’s manufacturer recommends. Before reassembling the tank and valve, brush and lubricate the O-ring. If the O-ring is dry or warped, this is the perfect time to replace it.

Don’t forget to prep the filter for use. You’ll need to set the valve to rinse, then backwash, then back to rinse. If the tank has a slide valve, simply run a backwash cycle. Always turn off the pump when you change valve settings. When you’re done prepping the filter, you can set the valve to filter.

FAQs

What Are Microns?

Microns, also called micrometers, are a form of measurement. One micron equals one-millionth of 1 meter. Pool filter manufacturers use the micron measurement to describe the width of particles that their filters can trap. To help you visualize the size of 1 micron, a single hair strand measures approximately 50 microns in width.

sand filters pool

How Do I Know When It’s Time to Replace My Sand Filter Tank?

While you do have to replace the sand once the edges become smooth and the granules can no longer trap particles, you’ll eventually need to get a new tan. There are several signs that indicate a tank has surpassed its useful life. The first sign you’ll probably notice is an odd pump noise coupled with a leaking port.

Sometimes, you’ll need to replace the tank for other reasons besides wear and tear. For instance, if the sand inside is relatively new but you still find yourself backwashing the filter more than once a month, the filter may be undersized for your swimming pool.

what kind of sand for pool filters

Why Do I Have to Sanitize My Pool If I Have a Sand Filter?

As you’ve read, silica sand has a filtration rate of 20 microns. However, many particles are much smaller. Bacteria ranges from 0.3 to 2 microns wide, and algae can be as small as 8 microns. Therefore, the filter is limited as to the contaminants it can catch. This means you must sanitize the water to ensure it stays hygienic.

Pool Sand Filters: Recap

Every swimming pool needs a filter. As far as filter media choices, you have three – diatomaceous earth, cartridges and sand. While each type of filter has its own set of pros and cons, sand is the media of choice for those who want to save money and spend less time on filter maintenance.

If you decide to go the sand filter route, you don’t necessarily have to use grade-20 silica sand. There are fill materials with smaller filtration rates and larger surface areas, such as ZeoSand, filter glass and Pollyballs. While sand alternatives offer many benefits, none of them are as inexpensive as traditional silica sand.

where to buy sand for pool filters

When browsing for a sand filter, your choice should be steered by the volume of water in your swimming pool and the horsepower of your pool’s pump. The gallons per minute of the filter can be a little bit more than the pump’s; however, you should never undersize the filter.

Once your sand filter is in place, familiarize yourself with the valve’s settings – multiport valves have more settings than slide valves. Make sure you replace the sand once per 5 to 7 years or longer for some sand alternatives, and backwash the filter every 1 to 3 months.

Top 5 Best In Ground Pool Filters of 2019

In the circulation system of a swimming pool, the filter is positioned after the pump. If there is one, the heater is then the next component the water travels through before the water reenters the pool. Every in-ground swimming pool needs a filter to remove unhealthy impurities like algae and bacteria and keep the water safe and hygienic.

in ground pool pumps and filters

Filters use one of three media – a cartridge, diatomaceous earth (DE) or sand. Of course, the type of filter installed in your pool is entirely up to you. Each filter media has unique benefits. Some are more efficient; others require less maintenance.

Regardless of the filter you choose, the most important part of your decision should be getting the right sized filter, which is determined by the volume of your pool and the flow rate of the pump. Undersize the filter, and your risk restricting the water flow and damaging the pump.

To give you a list of dependable filters for your in-ground swimming pool, we considered factors such as durability, efficiency and usability. If you can’t decide on the type of media or want to know how to size a filter, our buyer’s guide provides all the information you need.

Best In-Ground Pool Filters

Best In-Ground Pool Filter Buying Guide

Every pool needs a filter to remove the germs that lead to recreational water illnesses like diarrhea, E. coli infections, Legionnaires’ disease and swimmer’s ear. Cartridge, diatomaceous earth and sand filters are all capable of capturing dangerous germs and particles, but some media are more efficient than others.

in ground pool sand filters

When choosing an in-ground pool filter, you can’t just make a decision based on efficiency. You must also consider the amount of time you can spare to maintain the filter. A dirty, unmaintained filter isn’t doing your pool, or your health, any favors.

This guide will tell you how pool filters compare in terms of efficiency and maintenance. You’ll also find out how to do a few simple math equations, so you can get a filter that’s appropriately sized for your swimming pool.

Types of Filter Media

Outwardly, all types of in-ground pool filters look similar. Inside the filters’ housing, the media differs. The filter will either contain a cartridge, diatomaceous earth or sand/sand alternative. A cartridge filter contains one or four pleated, cylindrical media. As water flows through the cartridges, the pleats trap the particles.

Diatomaceous earth (DE) media is made from the fossilized exoskeletons of algae called diatoms. The DE used for pool filtration is heat-treated and formed into a powder-like substance. The DE powder is spread over fabric-covered grids that are secured by two manifolds. When water travels through the filter, the DE captures any impurities in the water.

Sand filters contain 20-grain silica sand, which are quartz granules approximately 840 microns in size. Water goes into the tank via a diffuser, traveling to the sand bed at the bottom. Particles in the water become trapped in between the granules while the now-clean water is returned to the swimming pool through laterals connected to a central standpipe.

Filtration Efficiency

People often gravitate toward sand because it’s the cheapest filtration media to buy upfront. However, it’s the least efficient of all three media, capturing particles from 20 to 40 microns. Sand lasts for about 3 to 5 years, which is longer than a paper cartridge’s lifespan of 1 to 3 years.

in ground pool filters

Synthetic and fiberglass cartridges have a slightly longer working life than paper ones, and many can trap particles as small as 10 microns. Cartridge filters come in single and quad configurations. A single-media cartridge filter is ideal for small or medium-sized swimming pools. Quad-filter setups are better suited for large pools that get a lot of use.

The initial price of a DE filter costs the most. Still, its lengthy lifespan of 10 years makes it a money-saver in the long run. DE filters are also able to trap the smallest particles, often down to the size of 1 micron.

Alternatives to Sand

Other granules are available for use in place of sand. In comparison to sand, filter glass, pollyballs and zeolite are able to capture smaller particles. All but zeolite have a longer lifespan. Filter glass, pollyballs and zeolite aren’t as dense as sand; therefore, less of these media are needed to achieve the same performance as sand.

Filter glass is made of recycled glass that’s crushed into fine pieces. This media holds a negative charge that attracts minerals and water. It can trap particles down to about 5 microns and boasts a lifespan of approximately 10 years or longer.

Pollyballs are simply small balls of polyester that you can use in the place of sand. It only takes 1 pound of pollyballs to equal the efficiency of 100 pounds of sand. While they achieve a filtration rate of 10 microns, pollyballs aren’t compatible with some clarifiers.

Zeolite can be natural or synthetic, but natural zeolite is derived from volcanic rock, and the natural type is often used for pool filtration. Depending on the specific zeolite media, the filter can capture particles anywhere from 2 to 6 microns. It’s also lighter in weight compared to sand.

Maintenance Considerations

Maintenance comes with the territory of pool ownership. DE filters are the most tedious to maintain. You have to backwash it yearly, but some are also equipped with a bump handle that shakes off the powder from the filter’s grids. You must mix the DE powder with water and add the solution to the filter after each cleaning.

best in ground pool filters

Sand filters require less maintenance than DE versions. Cleaning a sand filter involves replacing the sand once it begins to lose its efficiency. To replace the sand, you must first drain the water, take off the valve and suction or scoop the old sand. Since there aren’t many internal components in a sand filter, breakdowns don’t happen often.

Cartridge filters are the easiest type to clean; however, they must be cleaned often. These filters aren’t backwashed, but routine cleanings do consist of rinsing the pleats and blowing off dust after the cartridge dries. About once per year, a filter cartridge must be deep cleaned by soaking in a solution of muriatic acid.

Sizing an In-Ground Pool Filter

The right sized filter maximizes the pool’s ability to trap debris. While you never want to undersize the filter, we do recommend getting one a little larger than your calculations indicate. You’ll need to know the pool’s total volume in cubic feet – Multiply its length, width and depth (3.14 times depth for circle-shaped pools).

Then, multiply the cubic feet times 7.48. Take the volume and divide it by 8 (the average number of hours for a pool to effectively recirculate all the water it holds) to calculate the gallons per hour. Finally, divide the final figure by 60 to calculate the flow rate in gallons per minute.

You also have to consider the filter’s surface area. As far the surface area goes, there is no firm rule. However, a good guide is 3 square feet for a sand filter, 100 square feet for a cartridge filter and 36 square feet for a DE filter – These numbers are based on 10,000 gallons of pool water.

FAQs

How Do I Know When It’s Time to Clean or Replace My Filter?

Over time, the particulate matter in between sand granules causes pressure to build inside the filter. Similarly, particles accumulate on the grids of a DE filter, eventually increasing the pressure. Sand and DE filters are equipped with a pressure gauge. When the gauge reads at 10 psi above its starting pressure, it’s time for a cleaning or a replacement.

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Cartridge filters also have a pressure gauge, but particles are captured within pleats, so pressure building is an unlikely occurrence. If the cartridge is stained or worn even after cleaning, you need to replace the media. When cleanings become more frequent or you start having problems with algae blooms, the cartridge should be cleaned.

What Type of Valve Is Better?

The valve lets you control the filter’s flow of water. Valves come in two types – side and multiport. Side valves are specifically designed for side-mounted filters where space is limited. These valves only have a filter and a backwash setting. The filter setting is the standard cleaning cycle, and the backwash setting reverses the water flow.

Multiport valves can have up to eight settings, including filter and backwash. Rinse is the setting you should choose after backwashing to loosen any debris remaining in the pool’s pipes. Recirculate allows you to safely operate the pump while bypassing the filter, and the closed setting stops water from entering the filter when you service it.

Does the Pump’s Size Matter?

Absolutely. Without the pump, the filter can’t function. If the filter is too small, the pump will eventually overheat, and you’ll be looking at a costly replacement. Therefore, it’s crucial to match the filter’s gallon-per-minute flow rate with the pump’s flow rate.

The tricky part of sizing a filter to a pump is factoring in the pump’s horsepower. Usually, the manufacturer lists the pump’s flow rate in the specs and the operating label, so you don’t have to figure it out on your own. However, if you need a rough guide, a 1 HP pump has a flow rate of about 50 GPM.

In-Ground Pool Filters: Recap

Diatomaceous earth is the most efficient. It lasts the longest compared to the other two filters, but DE is the hardest to clean. Cartridges have the shortest lifespan, yet they’re the easiest to clean. Sand requires infrequent cleaning; however, the downside is a less efficient filtration rate unless you opt for a sand alternative.

what is the difference between in ground pool filters and above ground

Valves are found on all three types of pool filters. Some are mounted to the side, but most are positioned on the top of the filter. Side valves are usually found on cartridge-style filters. They are necessary for side mounting a filter, and they take up less space on small equipment platforms.

Multiports are the most common type of pool filter valve. Unlike the two flow settings found on side valves, multiport valves give you a lot of control over the flow of water. They offer as many as eight settings, so you can clean, rinse and service your filter with less hassle.

Finding the correct size filter for your in-ground pool only requires a few math calculations, none of which are complicated. It’s perfectly okay to oversize the filter, but don’t get one that’s too small. Make sure the filter meets the pump’s flow rate, and you should be good to go.