question about main drain


LifeTime Supporter
May 23, 2009
Trenton NJ
We are going on vacation (in about an hour or so) and I am switching to the main drain and shutting down the skimmer. The problem is, I seem to be getting air bubbles in the basket before the pump, more than usual. The pressure is being maintained but why am I getting air in the system when doing this?

Thanks, hope to hear from someone


TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
Silver Spring, MD
There are a couple of possibilities. Turning off the skimmers increases the suction, which lowers the pressure. Low pressure can allow air to come out of solution, forming small bubbles. The increased suction could also be revealing a small air leak in the plumbing that is normally too slow to be obvious.

The best plan is to leave both the skimmer(s) and the main drain turned on. If the skimmer(s) get clogged the system will just switch to the main drain automatically.