Keeping Filters Working Efficiently: Best Practices for Service Pros

Filters are often overlooked and water clarity problems are treated ineffectively as the filtration system should be addressed first and foremost.

Everyone in the industry agrees filtration is the key to clean water. That said, filters are often overlooked and water clarity problems are treated ineffectively because the filter should have been addressed first and foremost. This article will review a number of service and maintenance tips for different filter types, the most common mistakes when servicing and installing filters, as well as best practices to ensure the customer’s filter operates as efficiently as possible.

Filtration systems over the past 20 years

Over the years, the pool industry has seen a changing of the guard—of sorts—when it comes to the type of filtration system being used. For decades, sand filters were the most common pool filter in the industry. In fact, to this day, there are probably more sand filters in the marketplace than any other type.

However, approximately 15 years ago, many sand filters started being exchanged with cartridge filtration systems, as this equipment started to become more popular.

“In the U.S. Midwest, our pools hold, on average, 94,600 to 170,350 L (25,000 to 45,000 gal) of water, which are much larger than most pools found in the southwest,” says Dan Lenz from All Seasons Pools. “Therefore, when larger cartridge filtration systems were made available, we started installing more of them, as they didn’t need to be cleaned as often. Prior to this, however, all we installed were sand filters.”

On the other hand, Richard Deakin of Hollandia Gardens in London, Ont., has seen a rebirth in the use of diatomaceous earth (DE) filtration because of its ability to provide superior water clarity.

“Most of our competitive commercial pools use DE because they want to be able to have super-clear water quality, where they can see a dime at 5 m (16.4 ft) below the surface,” says Deakin, whose company provides services to pool and/or hot tub owners in southwestern Ontario. “Further, consumers have become more educated about this method of filtration and, as a result, we are installing more DE filters for residential applications.”

Pump sizing is a common mistake

Filtration systems, regardless the media being used, are designed to filter water within a certain range of flow.

“That said, one of the most common mistakes service technicians see in the field is a filtration system equipped with an oversized pump,” says Pentair Commercial Aquatics commercial sales and marketing manager, Mike Fowler.

In these cases, the pump pushes the water through the filter too fast, which impedes its ability to perform its job correctly. Therefore, it is extremely important to properly size the filtration system to the required pump flow to achieve efficient water filtration.

To size the filtration system correctly, it is necessary to determine the required turnover rate for the pool, as well as verify the proper filtration rate (typically 57 liters per minute [lpm] [15 gallons per minute (gpm)]/930 cm2 [1 sf] for a commercial pool). For example, a 757,082-L (200,000-gal) pool that needs a six-hour turnover would require a 2105-lpm (556-gpm) filtration rate. Therefore, the pump needs to provide this filtration rate (at least) at the given total dynamic head (TDH) and the filtration system would need to be sized to handle this flow rate. Doing this will increase the filtration system’s efficiency.

Incorrect chemical diagnosis

There are many different chemicals available in the marketplace that are used to keep pool water clean and clear; however, one of the biggest mistakes a service technician can make when diagnosing a water treatment issue is failing to check the pool filter first.

“Whenever I am presenting a seminar on chemicals and pool water treatment, I always start by saying, “Water clarity is only as good as the filter will allow it to be,” says ProTeam’s regional sales manager, John Bokor. “Pool chemicals can resolve many different water quality problems, but if the filter isn’t working properly, neither will the water treatment program.”

During the summer, the most frequent call service technicians get from pool owners is that their water is cloudy. Most respond to this problem by telling the customer to simply add a clarifier; however, a clarifier will not clear the pool water if the filter is gummed up and not filtering properly.

Sand filter best practices

Sand filters are still one of the top filtration systems used throughout the industry. That said, they need to be monitored closely to ensure the media inside the tank stays smooth and does not solidify. If this happens, the filter’s efficiency will degrade severely as water will not be able to pass through the sand. If this happens, the service technician should turn off the pump and open the filter casing to inspect the sand to determine whether the media needs to be changed or simply backwashed.

Maintaining the filter valves is also imperative. Failing to do so may result in the client having to replace the gaskets, as they can be a source for water loss.

It is important to know how to keep a sand filter functioning properly. One way to do this is by using a filter cleaner additive as it gives sand filters an extra boost to remain effective.

Another good tip for sand filter maintenance is to add a dry clarifier to help remove fine particulate. The dry clarifier coats the sand bed, filling in any nooks and crannies in the media, and is then simply washed out of the filter during the backwash without leaving any residual.

“Using a dry clarifier increases filter efficiency by penetrating the sand with a polymer formula and restores water quality after heavy rain and/or bather loads,” says Bokor. “The product attracts all matter as small as two microns and captures it in the filter.”

Terry Arko, a water treatment specialist with NC Brands/SeaKlear, says using a clarifier product can be an invaluable aid for sand filtration. Depending on the product being used, it can enhance the filter’s ability to trap particles down to 0.5 microns.

“These products are perfect for commercial facilities to keep pools clear and clean even during times of peak bather load,” adds Arko.

According to Deakin, when it comes to sand filters, they always take a proactive approach and replenish the sand every five to 10 years.

Cartridge filter cleaning tips

According to Lenz, one of his company’s most popular maintenance programs is their filter cleaning service.

“Our best ‘tip or trick’ when it comes to cleaning cartridge filters is using a little DE on the filter cartridge at the beginning of each season,” he says. “We use approximately 0.45 kg (1 lbs) of DE for every 9 m2 (100 sf). It is a fine coating which helps to make filter cleaning much easier.

“We bring all of our customers’ filters into the shop to clean. Any debris on the cartridges that are pre-treated with DE simply falls off without any intensive labor.”

Bokor recommends pool professionals should always chemically clean all types of pool filters at least once a year. For instance, products that contain a mix of wetting agents, surfactants, cleaning compounds, and release agents will help loosen and remove oils, combined organic matter, calcium deposits, and biguinide polymer materials. These products are compatible with a range of sanitizers and filter types, and can also be used as a backwash or a soak cleanser.

“When cleaning sand filters it’s important to turn off inlets for all chemical feeders, then with the pump running, and the filter in the backwash position, add 180 to 475 mL (6 to 16 oz) of filter cleaner through the skimmer. It can also be added directly to the filter media and should be allowed to soak for at least four hours. After soaking, start the pump with the filter in the backwash position,” he explains.

For customers using cartridge filters, Hollandia Gardens offers an annual cleaning service.

“We provide a two-step chemical cleaning; the first step involves a degreasing wash, while the second step is a descaling wash,” says Deakin. “We generally remove all of our clients’ filters in the fall, perform the two-part chemical bath, and then reinstall the filters.”

Cartridge filter cleaning services

Pool maintenance companies interested in offering a filter cleaning service may want to use the following guidelines to ensure the best cleaning results for their customers.

1. Hose off the filter

Using a standard garden hose, rinse off the filter from top to bottom. Never pressure-wash the filter, as the bands holding the pleats in place can snap under pressure. Should this happen, the pleats will collapse on themselves, reducing the surface area of filtration.

2. Soak the filter

After hosing down the cartridges it is important to put the filters through a soaking process. This can be done using 208-L (55-gal) plastic drums to allow the filters to soak overnight in muriatic acid and a filter cleaning agent, which is available from most pool chemical manufacturers.

3. Repeat soak

Once the filters have soaked overnight, some pool technicians will lightly rinse the filter and place them in a freshwater drum to soak again. Once finished, an optional liquid chlorine bath can be performed to brighten and lighten the filters.

“We do this final soaking so they look nicer when we return the filters to our client,” says Lenz. “In some cases, these soaking procedures may need to be repeated depending on how dirty the filter cartridges are.”

4. Air dry

Once the cartridge is clean, it is best to let the filter cartridges air-dry before using them again. Allowing them to dry completely gives the cartridge time
for the fibers to fluff back up, which is important because the fibers need to expand to be effective. If not, they can be pushed down easily, which reduces the filter cycle.

“We suggest the pool owner have two sets of cartridges,” says Lenz. “This allows the client to continue using their pool while the other set is being cleaned.”

The service technicians that do the best work are those who take the filter media with them when they close the pool for the season, clean it at their shops, and return the filter ready-to-use in the spring when they re-open the client’s pool, says Bokor.

“This is beneficial in two ways,” he adds. “Not only can the pool professional charge extra for the filter cleaning service, but they also have a customer with cleaner pool water all summer.”

Pool Craft, in Richmond Hill, Ont., which provides pool and hot tub maintenance and service across the greater Toronto area, also offers its customers a winter filter cleaning service. In fact, Cassidy Franks, the company’s operations manager, says if their customers’ filters look as though they need to be replaced after cleaning them over the winter, they suggest keeping them on hand, as using them during spring pool startup can be beneficial.

“The pool is typically at its dirtiest point during the opening season, thus the cartridges are filtering more debris than usual,” he explains. “Therefore, we recommend using the original set during spring opening to get the filtration process started by clearing heavier debris from the pool.

“Once the pool water is clear, the new filters can be installed to provide a more productive filtration process over the course of the summer. This will also extend the lifespan of the new filter cartridges.”

The importance of filter pressure

A service technician can save valuable time and resources during the busy summer months using a simple measurement—filter pressure. The change in pressure differential (pounds per square inch [psi]) can help a service technician determine if a filter is dirty and may need to be cleaned or simply backwashed—even over the phone.

For this to work, it is important to keep a log of the filter pressure on each pool being serviced. This can be done by making a note of the filter pressure in each customer file when opening their pool. This way it can be easily retrieved and referred to as needed. Having an archive of this data can also help when troubleshooting problems such as cloudy pool water or a malfunctioning heater.

For example, if a client calls with a problem, the first thing a service technician should do is open the customer file and ask them to check their filter to provide the pressure reading. If it was 18 when the pool was opened but is now reading 32, the customer can be instructed to backwash their filter, which in turn should solve the problem with their heater, as restoring water flow will allow it to function, and the pool water should also start to clear up.

This best practice can help a pool service company operate more efficiently, as some homeowners invariably seem to call with water clarity issues right before a big pool party or a long weekend. Therefore, it is great to be able to solve these types of problems over the phone rather than trying to squeeze them into a service technician’s busy schedule.

“We are diligent in keeping a log of all of our clients each time we service their pools,” says Lenz. “One of the most important figures we note is the initial psi on the gauge at the top of the filter tank. In fact, our technicians log 40 to 50 items via mobile device when servicing a client’s pool which immediately gets entered into their file in our business management software.”

Filter pressure and variable speed pumps

Another challenge with filtration systems and filter pressure has come to light with the advent of variable-speed pumps (VSPs).

“In the past, the pump was either on or off and service technicians took the psi measurement when the pump was on,” says Fowler. “As these pumps do not constantly run at full speed it becomes harder to get an accurate psi reading because as flow increases, pressure also increases, but not necessarily because the filter is dirty.”

According to Lenz, one of the best practices used today is to have the client turn their pump to full-speed once a week and take note of the psi at this time.

“We tell our customers to keep a log on their filter and to call us when the psi increases beyond 2.25 kg (5 lbs),” he says. “This is now a part of the weekly maintenance we recommend to clients, along with cleaning the filter baskets, skimmer, etc.

“In the past, it was common to watch the psi reading and if there was a 4.5 kg (10 lbs) increase, it was time to backwash (i.e. clean) the filter,” Fowler adds.

“With cartridge filters, however, it’s safer to advise cleaning the filter when there is a 2.25 kg (5 lbs) increase in pressure,” he says. “Sticking to this rule of thumb can prolong the life of the filter. If the pool owner waits for a 4.5 kg (10 lbs) change in pressure, the pleats will begin to collapse and the bands will start to break.”

Automatic controllers

An automation system can be beneficial when it comes to alerting the homeowner or service technician when a dirty sand filter may need to be backwashed.

“Rather than having to perform manual checks weekly, an automatic controller can also be used to set a backwash schedule based on psi readings,” says Fowler.

That said, automatic controllers can be an invaluable addition to a pool’s filtration system. With an automatic backwash controller, the need for a service technician to be present to perform this maintenance procedure—although recommended—is not necessary because the parameters set in the controller will automate the backwash process when it is time to do so.

“Most backwash cycles will occur when you see a 10 to 15 psi increase from starting clean filter pressure,” says Fowler. “Automatic controllers can be set to backwash the filter when this pressure increases, while some units can be programmed to backwash on a specific day of the week or time of day. Additional backwash controllers are also available and, although automated, require someone to activate the controller.”

This article was written by Aimée Samuelson and originally appeared on Pool & Spa Marketing [link].