How to check for leaks


Active member
Jun 23, 2008
How can I find leaks on the suction side of the pump?

When skimming, the pump basket fills nicely with nearly no air bubbles. But, when the vacuum hose is attached, the basket water level drops and I get a lot of bubbles in it. (It gets worse the longer the hose is attached.


Mod Squad
TFP Expert
Apr 4, 2007
SW Indiana
When you vacuum, you restrict the flow into the skimmer. This can cause bubbles two ways: First, the extra suction from the pump could make a marginal connection start to leak. The second is that the lack of water coming in causes cavitation, which doesn't indicate an air leak, just an absence of sufficient water for the pump's requirement.

For an air leak, you might see water squirt out when you shut the pump off. If you suspect an area, you can pour a stream of water over the spot to see if you get an improvement in the bubbling. You can also cover the area with shaving cream and look for voids that will be created by air pulled in through a leak.

For cavitation, about all you can do is slow the pump down or improve the flow through the vacuum to the pump. Make sure the hose isn't kinked. It's possible that the additional suction could be causing the suction hose from the skimmer to the pump to partially collapse, which could cause the problem, or make it worse.


LifeTime Supporter
TFP Expert
Mar 29, 2007
Coastalish 'down easter'
Xebec, welcome to TFP!!

John has you covered on some of the most probable causes, but there is one even more simple than those - switch the end of the vacuum hose that you put in the skimmer to be on the vacuum head! Many of the vacuum hoses have a swivel cuff on one end to prevent the hose from twisting too much - that end should be on the vac head, because of the swivel it can draw air if used on the skimmer side 8)