Cheapest and Most Affordable Way to Filter Your Pool Water

Written By Timothy Te

17th March 2021

It’s normal to want to save money when it comes to pool maintenance and today we’re looking at one of the things that contribute the most to pool maintenance expenses. If the title didn’t give it away, then what we’re going to talk about today is about the pool pump and filtering pool water in general.

Pool maintenance expense when it comes to filtering pool water is pretty straightforward. If you’re running your pump, you’re filtering your water. So basically, every time you filter your water, you’re spending money.

How much water do I need to filter?

Simple logic would dictate that if we had 40,000L then we would need to filter 40,000L right? Well, sad to burst your bubble but it doesn’t work like that. A lot of pool professionals would say that one turnover isn’t enough to fully filter all of your pool water, why? Because once the water gets filtered and returns to your pool, it dissipates and mixes with unfiltered water, so you’re actually filtering less and less “unfiltered” water the longer you run your pump.

How many turnovers are needed to fully filter pool water? Well, one turnover effectively filters around 60-65% of all of the pool’s water, two turnovers filters about 85% of the water, three turnovers filters around 95% of the pool water, and four turnovers filter about 98% of all the water in the pool. Since we’re getting diminishing returns, the sweet spot looks to be three turnovers so that means for a 40,000L pool, we’d need to filter 120,000L of water to filter 95% of all of the water. Following me so far? Great! Moving on.

Note: Need to know the exact volume of your pool? Check out our guide on how to measure your pool here.

How long do need to run the pump?

For a standard 1.5hp single-speed pump which has a flow rate of around 300-320 litres per minute (let’s go 300 lpm for simplicity’s sake), this would mean that one turnover of your pool would take just a little bit over 2 hours or if we want to do three turnovers, we have to run it close to 7 hours. Yes, this sounds just right as we usually recommend running your pump for at least 6-8 hours per day to fully filter your pool water.

How to Save on pumping costs

Sold out

The only way we can actually save on pumping costs without risking green pool water is to switch out our single-speed pump for a variable speed pump. Now a lot of people will say, well, if you’re just going to be using a pump that runs at a lower speed, it would mean that we would have to run it for much longer to get the proper filtration and that would basically cost the same right? Well, that statement is partially correct in the sense that we would have to run the pump longer but the cost is between night and day.

The phenomenon involved in this reduction in cost is known as The Pump Affinity Laws. Without going too deep into the science, the best way to explain this is if we needed to reduce the flow rate of our impeller by 50% it doesn’t mean that we have to reduce our power usage by half, but instead, we actually reduce power usage by FOUR times.

In layman’s terms, taking the same example we had earlier with a 40,000L pool with a 1.5HP single speed pump, with an equivalent variable speed pump running at half the speed, we would need to run it at 16 hours. BUT we would be running it at a quarter the cost as we would a single-speed pump. Basic math notwithstanding, we would be saving 50% in energy costs in achieving the same amount of filtration!

Note: This is a greatly simplified explanation, but many variable speed pumps like the Water TechniX Pump Dual ECO Variable speed have other optimizations that will lower energy consumption up to 75%

Further Reducing Filtration Costs

To further reduce your filtration costs, we suggest the following (free!) steps to do. Well, they’re not exactly free because you’re going to be spending a bit of time, but hey, think of it as a free workout!

  • Ensure that your skimmer baskets and pump baskets are clean and clear before running the pump - by doing this, you’re effectively ensuring that the flow rates aren’t being impeded and you’re getting the maximum available flow rates that your pump is providing.
  • Skim and scoop out all visible debris - Nothing much to say here, by preventing debris from getting into your skimmers, you’re optimizing the flow rates.
  • Backwash your sand filter or clean your cartridge filter elements - Common sense dictates that dirty filter elements will not filter your water properly, so keep them clean and keep them efficient!

Even reduce your filtration costs more!

Sold out

Sold out

This next tip isn’t an obvious one since it will require replacing your filter with a much larger one. Wait, what? A larger filter? To boil this point down to just a couple of lines, we’re passing the same amount of water, at the same cost, through MORE filter elements. This means better filter efficiency, less filter maintenance, and cleaner water all around. We won’t be going through all of the advantages of having an oversized filtration unit, but if you’re interested in reading more about having an oversized filter, you can head down here where we answer, can a filter be too oversized?

Wait, what? Even more filtration cost reduction?

Sold out

And finally, our final tip on how to reduce the cost of filtration reduction (less pump runtime) is to enlist the help of a robotic pool cleaner like the Tornax TX30. How will this reduce our pool filtration costs? It all boils down to energy consumption.

Robotic pool cleaners filter the water while they scrub and clean your pool surfaces with their built-in filters. This means that the robotic pool cleaner filters out the dirtiest pool water as it goes! Yes, automatic pool cleaners like suction pool cleaners and pressure side pool cleaners filter your pool water as they go by pushing the water through your filtration system, but let’s not forget that they use your pool pump as well. Energy consumption-wise, a standard 1.5hp pool pump draws anywhere from 1,500-2,000 watts while a robotic pool cleaner can draw anywhere from 180-200 watts and that represents a savings of anywhere from 80% to 90%!

Conclusion

Many of our recommendations include getting newer pool equipment like energy-efficient pool pumps, robotic pool cleaners, and larger filtration systems, all which entail some added expense. But let’s keep in mind that filtering your pool water isn’t a one-time expense! The reason why it costs so much is that it’s an ongoing expense that we have to do day in and day out. By getting more efficient equipment, not only are we getting the same amount of work done more efficiently, but the savings will actually pay for themselves in the long run!

Mr Pool Man is also working with a couple of payment processors that will allow you to stagger the payments for new pool equipment, making it easier on the pocket to get the best pool equipment! For more information, check out our payments page here.

Do you have any questions about this topic or the featured products? No worries, we're here to help! Drop us a question down below and we'll get back to you ASAP.

Happy swimming :)

We Need This
We Need This
We Need This
Thank you!
Written By

Timothy Te

Pool Guru at Mr Pool Man

Sign Up for Offers, New Products, DIY Tips and More