Hot Tub Filtration
Author: Alan Schuster
I am a graduate of the City University of New York, with a B.S. Degree in Chemistry. My experience in the Swimming Pool and Spa Industry goes back over forty years.
During this period, I have helped tens of thousands of consumers and dealers solve pool and spa water chemistry and water quality problems.
Conjure up some images, of spas filled with steaming, warm, turbulent water, and you’ll want to get in and enjoy the relaxing and soothing benefits, of the hot water experience. Everyone wants a spa that looks crystal clear, does not have an over-powering sense of being chemically treated and is sanitary, so as to avoid the risks of illness and irritation.
In order to accomplish this, three things must be employed: an effective and easy to use filtration system to remove debris, wastes and particulates, the presence of a suitable sanitizer, at a safe and effective level and the maintenance of proper spa water chemistry, for bather comfort, sanitizer effectiveness and protection against corrosion.
In swimming pools, filters come in a variety of types and sizes. Size is not normally a major consideration, because the filter and pump are set away from the pool. Better filtration can be achieved, by using filters that use media, in depth, to remove finer and finer particles, as water descends through the layers of the filter media.
In a typical spa, the filter and pump are housed within the spa cabinet, putting a limit of the size of the filter, that can be accommodated. The goal is to achieve good filtration, within the design limitations, dictated by the available space, within the spa cabinet.
For this reason, cartridge filters have become the product of choice, as their compact size and designs make them more practical. There are design and performance differences, that should be considered, in order to make a better-informed choice. Trying to offset poor filtration, by increasing chemical treatment, is ill advised, as it only hastens the buildup of chemical byproducts and changes in the water chemistry.
A drip coffee maker, is an example of a cartridge filter, in its simplest form. Ground coffee is placed in a paper filter and hot water is trickled into the filter, at a suitable rate. The paper filter keeps the ground coffee in place and the brew passes through the filter. In the beginning, the water quickly passes through the cartridge, but starts to slow, as the finer coffee grounds start to clog the filter. If you allow the brewed coffee to stand a while, you will notice fine particles of coffee grounds, that managed to pass through the paper filter. The simplicity of the systems works well for a coffee maker, but a spa can benefit from something more, than just a simple paper cartridge.
Most spas use a pleated filter cartridge. The pleated design increases the available surface area and improves flow rate and performance. It is best to filter at lower speeds, as there is less of a tendency to push particulates through the filter. Filters are rated at gallons or liters per minutes, for optimum performance. The more wastes and sediment, that can be removed by filtration, the better will be the overall water clarity and quality. There are filters that can remove microorganisms and this sounds like a great idea.
However, it does not replace the need to have active sanitizer present in the spa. So long as people use a spa, it is inevitable that microorganisms will get introduced, into the spa water. Any filter that is effective enough to remove something as small as bacteria will probably clog too quickly, to be practical.
In the final analysis, we choose a filter because it is practical, easy to use, requires little maintenance and does what is required, to help achieve optimum water clarity and quality. Every spa is different, in terms of how it is used, how many people use the spa and how it is sanitized. These factors determine how many hours are required for adequate filtration and sanitation. In many cases sanitizing and filtering take place at the same time.
The standard pleated cartridge is reasonably efficient, providing that the sanitation and chemistry are well-maintained. The filter should be cleaned on a regular basis, which varies based on use. Hosing the filter can become a bit messy, but there are products that help simplify the cleaning task.
Sanitation problems can lead to filter clogging and are best remedied by soaking the cartridge, in a bath containing some chlorine. Test the sanitizer level and shock treat, as necessary. Sometimes hard water causes deposits to accumulate and this increases the filter pressure, reducing the flow rate. Soaking the cartridge in a modestly acidic bath can help dissolve the accumulated minerals. Pleated cartridges don’t last forever and should be replaced, based on the product manufacturer’s recommendation. While the common pleated filter can do the job, there are better and more capable filter options, that still fall within the category of cartridge filters.
In depth filtration is a better and more effective approach, towards improved results. Instead of having water pass through a pleated paper cartridge, better results are possible, when a media depth, polypropylene cartridge is used. The dense polypropylene media removes smaller and smaller sized particles, as the water forced through the filter. Larger sized particles are removed first and progressively smaller micron-sized particulates are removed, as water passes through the depths of the media.
This more advanced type of filter cartridge is simply replaced periodically, as cleaning is not a recommended option. Filter cartridge cleaning can be a messy chore, so simple replacement is an appealing alternative, especially when it is accompanied by better results.
Arctic spas feature two filter cannisters, both of which can accommodate a cartridge, as a means of further improving results. The choice of paper or polypropylene cartridges is left to the spa owners, but the in-depth polypropylene cartridges do provide greater convenience and improved results. How a spa is designed can affect filtration results and debris removal. Minerals and debris, tracked in on the soles of bather’s feet, tend to settle to the spa floor. Arctic Spas have footwell filter intakes, that help remove the heavier debris, that tends to settle to the spa floor. Arctic Spas feature two skimmers, with weirs, that telescope, in order to accommodate changes in the water level, when bathers are entering or exiting the spa.
In a swimming pool, the cost of electrical power required to operate the pump and filter, for a reasonable length of time, can be a significant expense. For this reason, variable speed or two speed pumps, have become more and more popular. Some localities have banned the use of single speed pool pumps. Switching to a 2-speed pump and doubling the amount of filtration time, would seem to cancel the benefit. However, the physics show something else. Each hour of operation, at low speed, uses 1/8 the electricity and even if you double the time, there is still a 50% cost savings. In a pool, lower water flow can lead to the development of areas with poor circulation and reduced sanitizer presence.
To avoid the potential for these problems, it seems best to run pumps at high speed, for part of the time. However, in a spa, even at low speed, you still have a good rate of water turn over and effective distribution of sanitizers. Low speed is ideal for filtering and sanitizing. High speed can be what makes your hot water experience special: bubbles and agitation are an integral part of the hot water experience. Arctic Spas have a bypass valve, built into the plumbing system, that allows water to bypass the filter, whenever the pump is set on high speed or there is a blockage. The programable, topside controls allow you to control the filter running time and speed, from 0 to 24 hours.
Arctic Spas continues to refine their patented filtration systems and develop new ideas, to enhance the user experience. The objective has always been to maintain your spa water, in a safe, clean and sanitary way, and to do so with the least amount of work, for the spa owner. Spa filtration is a pillar of proper water maintenance and your Arctic Spa is designed to allow you to select the best options and help you reach your goal of superior water quality and ease of use. Spas are not one size fits all.
They are used by different numbers of bathers, sanitized in different ways, filled with source water of different qualities and come in a variety of sizes. In some respects, your spa is unique. You don’t simply fill it with water and plug it in. Getting started can seem a bit daunting, but with help and guidance from your Arctic Spa professional, you can be on your way to years of enjoyment. Filtration is an integral and important aspect of spa maintenance and Arctic Spas has the products and options that will help you meet your needs.
You’re not on your own.
You have product options, that have been designed for use with Arctic Spas, and their performance has stood the test of time. Choosing the right spa filtration system will help, with sanitizing and general maintenance. The more debris, wastes and byproducts, that you can filter out of the water, the more sanitizer will be available for sanitation. Your Arctic Spa professional can help you with the choice of a sanitizer or a combination of sanitizer systems.
Making the right choice helps everything fall into place, with less time and effort spent. Water chemistry not only affects how well a sanitizer works, but affects water clarity, bather comfort and spa equipment, as well. Regular water testing must be part of the routine of spa maintenance, to help keep minerals for precipitating out of the water and causing hazy conditions.
Today’s products for filtering, sanitizing and water testing are better and easier to use, than ever before. With the right choices and a little advice, from your Arctic Spa professional, you’ll enjoy getting into hot water.