Relief valve open, DE slipped into pool via main drains...


Well-known member
Oct 12, 2009
I went to add chlorine to my in line chlorinator and also opened the air relief at the same time. Upon returning to the pad from getting the chlorine, i glanced at the pool and saw DE oozing out of the main drains. The pump basket was also full of it and gurgling like crazy.

I swear i had opened the air relief before but I think that was a bad idea. Not even sure why i did it, but thought that is what i always did. So should i leave air relief closed with chlorinator opened up?

Melt In The Sun

TFP Expert
LifeTime Supporter
Oct 29, 2009
Tucson, AZ
Makes sense to me. Opening the air relief valve let water flow backwards from the filter to the pool, carrying DE (plus whatever was caught in the DE) with it.