Then it isn't a closed loop but a standard return.
It could be a number of things, but based on the fact that hubby is out playing hockey I would think that your sump may be running dry and air is being sucked in.

I already tried that... and boy it is good I have lots of water made already.:wink:

Check the sump.

I know it'll probably suck, but you might have to check the actual pump. Take the pump apart and clean it out. I don't imagine the sump could be runing dry...if you're anything like me you check it religiously

The sump is full. The water gets sucked into the return pump from the bottom of the sump not the top. The water would have to be drained right out for it to be sucking air. I feel that the pump is cavitating and on it's way, out but the LFS INSISTS there is a pin hole in my system. I don't know much abut how the system works but I cannot see how it is possible to have a pin hole to be honest. Sorry about my lack of knowledge on the set up. I watched it get built but do not know the technical names of all of it. I just take care fo the entire system except for broken things.:wink:

That is going to really SUCK (no pun intended:razz:) but that is my last option. I want to whine and give the excuse f... well I have filter socks how can there be anything in there, or the skimmer would have got it. It is the last option I have at the moment but at least I have ball valves to turn the water off as well as check valves.

I won't do it until morning now since I learned nt to touch anything before bed unless it was an emergency... Thanks for the tip though, it is a really god one.:wink:

Make sure the inlet to the pump is clear.

Cavitation and aeration are two different things. If the intake to your pump is blocked partially to fully cavitation will occur. If air is getting into your pump then airation is occurring. Im not sure if cavitation could cause microbubbles but checking the intake for restriction would be one to check on top of air leaks.

Thanks everybody I will check it out, just not tonight. If I touch anything this late Murphy's law will kick in... With well over 325g of water it could be ugly.

You guys are the best!!!:razz:

Just curious, what kind of pump is it?