Backwashing your sand filter
It is recommended to backwash sand filters when the pressure reading on the tank reaches from 5-9 pounds above the normal operating pressure. You should expect to be backwashing a sand filter once a week, depending on how dirty your pool has been. For a commercial swimming pool where it is being used by many people continuously, you might find yourself backwashing about every few days.
The backwashing process
Clean all the debris from the skimmer basket and filter pump basket. Remove all debris that might be trapped around the main drains such as leaves, sticks and toys. If you don’t remove this debris then it is possible the backwashing process might cause these items to force back into your pool. Make sure you have turned off the power to the system and proceed as follows:
- If you have a shut off valve in the backwash discharge line make sure it is in the open position.
- Turn your backwash lever to the slot marked “Backwash”. Turn on the pump and let it run until the discharged water looks clean and absent of dirt. You should be able to view the water clarity through the sight glass.
- Turn the pump and system off and turn your backwash lever back to the slot marked “filter” Turn the pump and system back on.
NEVER move the backwash valve while your pump is running! Make sure the pump and entire system (for added safety) are in the off position. It might be a better idea to turn the pool system breaks off just in case you have an automated system that could activate the system (due to its programming) while you are servicing it. Serious injury or damage to the system can occur if you do not follow this warning.
How to change the sand in your filter tank
It is recommended to remove and change the sand inside your filter tank about once every five years. If your pool has been running dirty, you have been fighting algae problems on a regular basis then you might need to change the sand within about six months or so.
- Start by backwashing your filter per the instructions listed in Backwashing Your Filter, section A through C.
- Open the air relief valve located at the top of your filter tank as to release the vacuum and allow the water to drain from the tank. (you should start to hear a slurping noise)
- After all the water has drained from the filter tank, remove the fastener holding the top portion of the tank together and open the tank.
- Remove old and thoroughly clean out tank.
- Inspect tank and all parts for cracks and damage. If you notice cracks or damage you will nee to replace those parts. All the separate parts for you filter can be found here.
- Wipe clean the large “O” ring that was sandwiched between the top halve of the tank. If the “O” ring is getting dry you might have to lubricate it using the approved lubricant.
- Fill the filter tank about half way up with water and start refilling the tank with the appropriate amount of sand. The require amount of sand should be posted on your filter tank and also in your owner’s manual.
- Reassemble the top part of the tank and all parts that you may have removed during this process.
- You should backwash the filter one more time until you see clear water passing though the sight glass.
- Place the lever on “filtration” and you have completed your task!