little psi change during slam

[abfab]

Normally I can get my pool crystal clear within 24 hours so dealing with a swamp is new to me. I just had a new pump installed. Went from 1.65hp to 2hp. I opened late due to pump replacement and unusually mild winter/spring. I'm on day 3 of slam. Pool is very cloudy. I can almost see the bottom of the shallow end but not quite yet.

Yesterday I backwashed my sand filter and psi went from 12 to 8. I did it again today and it only went from 11-10.5. I expected it to go down to 8 again. What would explain this? Water in the sight glass looked clear after about 30secs. I usually backwash for 1 min or until sight glass is clear then rinse for 30 secs.

 

[needsajet]

Nice to meet you via TFP.

Next time you backwash, try 2 mins and see if that makes the difference. I find I need around 2 mins backwash, and likewise around 30 seconds rinse, as you've been doing.

 

[abfab]

Nice to meet you via TFP.

Next time you backwash, try 2 mins and see if that makes the difference. I find I need around 2 mins backwash, and likewise around 30 seconds rinse, as you've been doing.

I tried that yesterday and this time it went from 10.5 to 10. Water in the sight glass was clear pretty quickly again. Checked this morning and still sitting at 10. My only guess is that somehow the 8 I saw was not accurate? I don't know how but my only theory is that I checked too quickly and there was a lower flow rate. It doesn't seem that the gauge is broken. No clue!

Pool is still cloudy but seeing very small daily progress. It seems that my sand may be too clean now that it's not picking up the small particles well. Will wait a couple of days and recheck the gauge reading.

 

[needsajet]

Makes sense yeh. I'm always happiest when the filter is a bit dirty. An option is to add some Pool grade diatomaceous earth (pool DE) via the skimmer. Try 1/2 a cup initially after back wash. Could be up to a full cup, but try not raise pressure more than 1 PSI due to the DE addition. When it works, pressure may rise quite quickly as the filter catches more of the cloudiness. Good luck with it