Choosing the right filter for your pool is not always easy. However, before buying a filter, you should know all the details regarding the swimming pool so that you can buy the best filter available. Then, buy the filter so that the pool is kept clean when used for swimming.
Step
Step 1. Find the surface area size and water volume capacity of the pond
Swimming pools are available in various forms. However, there are two common types: rectangular and circular. Depending on the pool you buy, make sure you calculate its size using the right math formula.
- The area of a rectangular pool can be calculated easily using the formula Area = Length x Width.
- If your pool is circular (usually in a hot tub or children's pool), its area can be calculated using the formula Area = 3.14 x radius^2
- You can calculate the area of the pool yourself, but if the pool has just been purchased, the size should be given right away.
Step 2. Find the maximum volume of the pool
The next step is to find the pool volume to find out how much water can be channeled through the filter in one minute. This is called the flowrate. The flowrate size varies depending on the type of pool you have. Make sure you take this into account to maximize the filter to be used.
- To get the pool volume, divide the maximum volume of water the pool can hold (you can find this when you buy the pool) by 360. The result is the number of liters of water that passes through the filter in one minute.
- We recommend getting a slightly larger filter for the pool for maximum efficiency.
- If the filter flowrate is too large and the operating pressure is too high, you can increase the pipe size in part or all of the piping system, and this will reduce the system's operating pressure.
- All filters have a minimum and maximum flowrate that must be matched to the pump capacity. If the flowrate is too weak or strong, the filter will not operate properly. Make sure the filter you get can handle the amount of water in your pond.
Step 3. Determine the pool turnover rate
This means that you need to know how long it takes the water to complete one full cycle through the filter. Most government health codes require filters to have a minimum turnover rate of two full water cycles within 24 hours.
- The minimum turnover rate is the one that rotates the entire pool water within 12 hours. Today's pools typically have a turnover rate of 8-10 hours.
- If the pool will be used commercially, semi-commercially, or needs frequent rotation, we recommend choosing a filter that allows you to rotate the entire water volume at least 4 times per 24 hours.
Step 4. Choose the right filter
The correct filter size depends on the size of the pond. To maintain good water clarity, you should run the pump every day so that all pool water is rotated. All filters have a design rating of liters per minute and a turnover rate.
For example: a circular pond above the ground measuring 7 meters has approximately 51,000 liters. The Hayward S166T Sand Filter has a 10 hour turnover rate of 70,000 liters and works well with this pool
Step 5. Consider how much water resistance will affect the pool turnover rate
The faster the water moves through the pump, the greater the resistance it has.
- Choose a filter that will rotate the pool water at least in 10 hours. For filters, we recommend choosing a larger size. A larger filter will help keep the water clear.
- Don't forget that the faster the water moves through the piping system, the greater the resistance to flowing water. This means that slower pumps such as the low speed setting on a two-speed pump (2-speed pump) have increased flow per unit power at low speed, as opposed to the high speed option. Be aware that most low speed settings on a two speed pump will not meet the minimum flow required for the filter to function normally.
Step 6. Use all the collected information regarding the pool to find the most suitable filter size
You should be able to use simple equations without much trouble. Before entering all variables, make sure the volume size (in liters) is correct and determine the ideal turnover rate for all water that is rotated through the filter. The equation used to calculate the filter size is:
- Pool capacity in liters divided by turnover rate in hours.
- You will get the minimum required flow in liters/m (liters per minute).
- Divide the result by 60 to get liters/m.
- Find the pump that matches the calculated liters/m.
Tips
- Contact the pump manufacturer to help you determine the approximate head resistance (meters/kg) of the piping installation. You will need this information to calculate the number of liters per minute the pump is delivering.
- Prepare a list of common pool sizes, their respective capacities, a list of popular filter sizes, and their ratings as they will be helpful during the selection process.
- Two-speed pumps are able to effectively meet minimum turnover values while consuming as little electricity as possible. Try using two filters to maximize efficiency.
- The filter selected should be designed to have a flow rate approximately 15-20 percent higher than the measured liters per minute pool pump.
- Most older pumps are designed for a maximum of 30 psi while new filters have a maximum operating pressure of 30 psi and a maximum total pressure of 50 psi.
