Backwash & Rinse


New member
Aug 14, 2019
Spanish Fort, AL
Hi all!

New here and have a quick question! When I backwash, it appears that the water is "sandy" is this normal? I feel like I have to backwash for forever to get it to run clear before I rinse!

Also, after backwashing and rinsing, when i turn the pump back to filter.... i have air bubbles coming from my returns. Is this normal? It eventually clears itself up.


Well-known member
May 6, 2018
A little bit of sand laying in the glass is normal.
Forever is relative, how long is forever in this case?

I have a 250lb sand filter with a 2 speed pump. I've noticed just running it on low doesn't quite do it, but if I give it a few bursts of high speed it seems to stir the sand up better. I then continue backwashing on low speed. It takes a few minutes. I try to do it after we get a lot of rain and I have to drain some anyway.

I then follow up with a rinse until the water clears up. I then shut it off, switch to filter and turn it back on.
I don't recall seeing air bubbles but it wouldn't surprise me as I'm sure some air can get in depending on how the valve on the filter works.

Backwash literally pushes water through the filter backwards, stirring up the sand and pushing stuff out. Imagine literally plumbing your filter backwards.
Rinse, is basically putting the filter back into "Filter" mode, but instead of going into the pool it runs it outside to get anything that's left behind out of the clean side of the filter before going back into the pool.

If the water is coming out dirty or cloudy while backwashing the sand must still be dirty. The cloudiness isn't beaming down from Mr Scott. :D

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Welcome to TFP! :wave: It's not uncommon to see some sand in the sight glass. A good/thorough rinse cycle should clear it up. As for the bubbles, if they are not persistant, increasing in size/quanitity, or you are seeing a water level drop in the pump basket, you should be okay. It may just be some residual chruning/outgassing from the backwash at the filter. If the bubbles do get worse or don't go away, consider checking some basic things on the suction side for an air leak. Thes einclude:
- Pump basket clear lid O-ring for cracks and lubed good
- Good water level at the skimmer
- Weir (flap) at skimmer (if installed) working properly
- Any obvious leaks on the suction side.

As always, make sure to shut-off the pump when changing filter valve selection settings. Let us know if you have anymore questions. Have a good day.