Air in filter/return line

[scsteven]

Hello! I am having a problem that I can't seem to find described here on previous threads. I started noticing that I had an excessive amount of air bubbles in my return line. Looking at my pump basket, the water looks like rushing rapids you might see in a river. The pump hasn't lost prime, however. This causes the pump to run loudly (more high-pitched humming than usual). I haven't lost any pressure either. When I shut the pump off to try to re-prime it just to get rid of the massive rapid-like water in the basket, my filter (sand with about 1.5 cups DE added) regurgitates air and water through the skimmer and it is so forceful that it blows the skimmer basket and lid right out of it's spot and into the air!
I also now have a fine layer of white/gray dust on the bottom of the pool that I can't get rid of. Oh, I will mention that the pump (Hayward 1.5hp) is approx. 1yr old. My filter is 7 years old. New sand this year. No problems until last week.
Here's what I have tried so far:
I thought the air might be getting into the pump from the skimmer side. I checked for leaks and just to be safe, I replaced the hose from the skimmer to the pump. Nothing changed.
Maybe the gasket is bad on the pump basket lid, I first re-lubed it, then replaced it. Nothing has changed.
My next thought is that it is something with the valve head on the filter. ???
I welcome any and all thoughts on this perplexing matter!!! Thank you so much!

[Poconos]

Welcome to the forum.
There was a similar situation posted a while back but think I could find the thread? Anyhow, sounds like either the filter is plugged or there is an obstruction in the return plumbing which I think unlikely. The skimmer blowing indicates a quantity of air has become trapped in the filter and is under pressure. When you kill the pump the compressed air blows back through the skimmer. You say you haven't lost pressure but what is the reading and has that increased from past values? I'm also questioning the amount of DE you added and whether you have backwashed recently. Depending on filter size 1.5 cups can plug the thing up. I know...someone will chime in and tell you to dismantle the filter, use a 1/4 stick of dynamite and a jackhammer, wash the sand, make that a yearly routine, etc. Don't do that yet. One thing to try when you backwash is to stick a small hose into the skimmer to let it suck a little air during the backwash procedure. The air bubbles in the filter will churn things up more than a solid charge of water. There's a name for this procedure but I can't remember it.
Best I can do for now.
Al

[hrsdennis]

I wouold guess air is sucking in through the lid on your hair and lint basket. Hayward is famous for that, the pot itself warps and the lid will not seal no matter how much grease you put on the o ring.

Try greasing the ring again and laying a plastic shopping bag over the opening. Then insert the lid. See if this slows down the air leak.

Keep in mind, an air leak will be in the pump assembly or the pump to skimmer hose or fittings. Most likely the the lint pot lid.

Best of luck, Dennis

[scsteven]

Thanks for your responses.. My pressure gauge is reading 12#. I gave the filter a really long good backwash last week thinking that maybe it was gummed up. At that time it was up to about 18#. I did not add DE after doing that. I added DE last night right before I vacuumed and it was about 1.5 cups worth. The pressure reading maybe went up 1#. I'm thinking it is something in the filter causing this problem. I want to try both of your ideas to see if I can narrow this down. 1. Could you explain the bag idea in the hair/lint basket? I don't understand where to put the plastic bag exactly?
2. If I try the hose in the skimmer basket-- don't laugh-- I am assuming a garden hose and I turn it on and just stick down in there while it is pulling pool water also?

Thanks again!

[hrsdennis]

One way to tell if your lint pot housing is bad is to try and rock the lid back and forth. There should be very little movement. I am assuming here that your lint pot lid is one where you give a small twist and pull up to remove. If so, remove the lid, lay a plastic bag over your lint pot and replace the lid. The double layer of plastic will tighten the fit of the lid.

The hose Poconos is talking about is for the purpose of drawing air into the filter to help with the backwash. You would need maybe a short piece of garden hose or some surgical tubing possibly.

Hope this helps some, Dennis

[Poconos]

Dennis said it right. You have to remove any skimmer basket and get the chunk of hose down toward the bottom and you'll find it's kind of sensitive but you will hear the air being sucked in. You just want a little air, not enough to lose prime.
Al

[duraleigh]

Just a thought......there should be a drain plug or two at the bottom of the lint pot. Are those in snugly?