Introduction
Keeping your pool water crystal clear requires proper filtration and maintenance, and one of the most critical yet often overlooked tasks is backwashing your pool filter. If you’ve noticed cloudy water, slow circulation, or increased pressure in your filter system, it might be time to backwash.
But how often should you backwash your pool filter? The answer depends on your filter type, pool usage, and environmental factors—especially in South Africa, where dust, heat, and water quality can all impact your pool.
In this guide, we’ll explain what backwashing is, when to do it, and how to perform it correctly to keep your pool water sparkling clean.
What is Backwashing and Why is it Important?
Backwashing is the process of reversing the water flow through your pool’s sand or DE (diatomaceous earth) filter to remove trapped dirt, debris, and contaminants. Over time, your filter collects dust, leaves, algae, sunscreen, and oils, reducing its efficiency.
If you don’t backwash regularly, your pool filter can:
- Become clogged, reducing water circulation
- Increase pressure, straining the pump
- Allow dirty water to circulate back into your pool
- Cause higher chemical usage and maintenance costs
How Often Should You Backwash Your Pool Filter?
General Rule:
- Sand Filter – Once a week or when the pressure gauge is 8-10 PSI above normal
- DE Filter – Once every 4-6 weeks or when pressure rises significantly
- Cartridge Filter – No backwashing required (clean manually every 4-6 weeks)
Factors That Affect Backwashing Frequency:
- Heavy Pool Use – If your pool is frequently used, especially in summer, you may need to backwash twice a week.
- High Winds & Dust – Pretoria and parts of South Africa experience dust storms, which clog filters faster.
- Rain & Storms – Rainwater introduces debris and dirt, requiring extra backwashing.
- Algae Treatment – If you’ve had an algae outbreak, you should backwash after shocking your pool to remove dead algae.
How to Properly Backwash a Sand Filter
Follow these steps to backwash your pool filter correctly:
- Step 1: Turn Off the Pump – Always turn off the pump before changing the filter settings.
- Step 2: Set the Multiport Valve to “Backwash” – This reverses the water flow.
- Step 3: Turn the Pump On – Let it run for 2-3 minutes or until the sight glass shows clear water.
- Step 4: Turn Off the Pump Again – Always turn off before switching settings.
- Step 5: Set the Multiport Valve to “Rinse” – This settles the sand and removes remaining dirt.
- Step 6: Turn the Pump On Again for 30-60 Seconds – Then switch back to “Filter” mode.
Tip: Avoid over-backwashing! Doing it too often wastes water and removes beneficial bacteria that aid in filtration.
Conclusion: Keep Your Filter Running Efficiently
Regular backwashing is essential for maintaining a healthy and clean pool. The key is to backwash only when necessary—monitoring pressure levels, water clarity, and filter efficiency.