Can't Fully Prime The Pool Pump

[sjpoolowner]

Hello.

I have a in-ground pool with two returns. A few weeks ago I noticed that water is not really shooting from one of the returns. I just couldn't feel the water coming out, which I normally do. I checked the other return and it was shooting the water but felt somewhat weaker than usual. And I also noticed water bubbles coming out of it.

Then I checked the pump basket and found that the water level inside the basket was low. I could actually see water coming into the pump basket. I heard that it was supposed to be full of water.

So I tried to re-prime the pump. First, I opened the pump lid, cleaned the basket, filled the basket with the water (but I couldn't fill over the level of incoming pipe), closed the lid. Then I opened the air valve of the filter, started running the pump, and closed the air valve once water coming out of it.

But it didn't really work. The water kept circulating but I couldn't fill the pump bask 100% with water. The water level didn't really go up. I increased the pump RPM (I have a variable speed pump) from 2000 to 3000. That seemed help a little bit but not much.

Then I turned off the pump and blocked the skimmer using the plastic thing under my skimmer basket so that water could come only from the main drain. (I don't have any valves that control water flow. I can block the flow only from the skimmer side, but not from the main drain.)

I repeated the process and also increased the pump speed to 3000 RPM and that started to fill up the basket. However, I couldn't fill it up completely. It was like 95% full. It looks like water was touching the lid but there were a few air pockets / big air bubbles. That was the best I could so I stopped there.

Then today I noticed that the pump lost the prime again. The water is still circulating (weakly) but the water level in the pump went down to the previous level again. I've just re-primed the pump and again only could fill the basket like 90-95%.

The water level of the pool was normal. It was above the skimmer level.

My questions are:

1. Does this indicate there is a leak somewhere and air is coming in?

2. Why can't I fill the basket only up to a certain point? I also try to spray the water here and there on the pump but didn't resolve this issue.

3. Even after the 95% prime, I still don't feel the water from one of the returns at 2000 rpm. If I rev up the pump all the way up to 3000 rpm, then I see first air bubble coming out and then water from that return. Does this simply because the water flow is slower since the pump is not fully primed?

4. Will cleaning the pool filter help?

I have intelliflo VS-3050 pump. I also have a pool vacuum and a booster pump.

Thanks.

[Pool Clown]

These pumps do that. But if it worked better before, with that same speed, there are some things you can check.

That particular pot design REQUIRES a perfectly clean lid o-ring, and the groove that it rests in, as well as a clean surface that the o-ring will contact on the lid (see thru plastic).

Also, as the filter gets dirty, the flow will go down in the pool, so make sure that the filter is clean too.

[sjpoolowner]

Thank you. I cleaned the o-ring and the surfaces it contacts as best as I could and re-primed the pump (again water filled up to 90~95% of the basket) three days ago. The pump hasn't lost the prime yet, but I noticed the water level dropped a little bit. So it still looks like air is still coming in from somewhere.

Before suspecting leaks in other areas, I'd like to rule out the pump lid/o-ring first. During the last re-prime, I didn't put any lube to the o-ring as the user manual says not to do that because the original o-ring contains a permanent internal lubricant. But would you actually recommend putting something to make sure no leaks there? I have lithium general purpose lube. Will that work? Or should I put anything special?

[Pool Clown]

No lube on that particular o-ring is required. If it is filling to 90-95% on a variable speed pump. It would not concern me. Have you tried raising the speed (of the pump) to see if it fills up then?