Pressure Keeps Decreasing at Return Jet

[CaseyJones76]

I have a Proline sand filter and 1 HP pump running my 10k gallon above ground pool. When the pump is first turned on, the pressure at the return jet is strong. The gauge reads between 10-15 PSI. After an hour or so, the pressure at the return jet begins decreasing dramatically while the gauge still reads 10-15 PSI.

I've backwashed 2-3 times recently. The skimmer and pump baskets are clear, as well as the pump impeller.

My only guess is that there is an air leak somewhere before the pump. Could the ball valve be leaking? I should also point out that when my electrician was hooking up the ground to the outside of the skimmer, he accidentally drilled the hole for the screw in the wrong location. We plugged it up with rubber and silicone and it has never leaked water. Could this be where the air leak is?

I'm at a loss and appreciate any advice.

 

[MITBeta]

What does your water look like?

What does your latest chemistry look like?

 

[CaseyJones76]

What does your water look like?

What does your latest chemistry look like?

Water is crystal clear; chemistry is perfect. However when I opened this year I had to remove a lot of leaves and debris. I backwashed a few times after that. There are also bubbles in the pump basket...

 

[duraleigh]

Welcome to the forum !

Bubbles in the pump basket indicates a suction side air leak. It is possible that leak is pulling in enough air to reduce your flow at the return. I would find that air leak and see if that fixes the low flow.

 

[CaseyJones76]

Welcome to the forum !

Bubbles in the pump basket indicates a suction side air leak. It is possible that leak is pulling in enough air to reduce your flow at the return. I would find that air leak and see if that fixes the low flow.

That's what I'm thinking. The hard part will be finding the leak. Pump lid, o-ring, and drain plug look ok. I have a ball valve before the pump that may be the culprit. Also, like I mentioned in the original post, my electrician accidentally drilled into the wrong spot on the skimmer when bonding the pool. We sealed it up with no water leaks but I'm not sure if it could be coming from there.