Hi, I have a bleed-back well system so the water can drain from the well supply line back into the well to keep the underground supply line from freezing; in our area of Southcentral Alaska we can get upwards of 10 ft of ground frost. There is a snifter valve (like a tire valve) on the supply line to break the suction so the water can drain back down when the pump's shut off. Originally, we put in a 75 gal pressure tank with a float valve, so the air that builds up in the supply line when the water drains back to the well can be expelled from the pressure tank as the water recharges the supply line. Then the float valve closes, allowing the air to pressurize the water system. 2 yrs ago the original pressure tank sprang a leak. I replaced it with a smaller bladder tank because it would have taken too long to get another tank like the original (I had to leave town the next day). I also added an in-line water filter. At first all worked reasonably well, except when the filter would get dirty, then, for some reason, we'd get air in the line. Lately, though, we've been getting air in the line all the time, even with a clean filter (I don't know what the filter has to do with anything...). The supply line comes out of the bottom of the bladder pressure tank, so I'm not sure why we're getting air in the line; seems like the air would rise to the top of the tank and just have water coming out. I'm worried that my well is going dry, but it's been gurgling along like this for several months without getting worse. A couple of years ago I had to replace the pump but at first I thought the well was going dry, so I lowered a bolt on a string to see where the water level was. Got the damned thing stuck and had to break the string to get it out (minus the bolt) so I don't want to try that trick again. Anybody have an idea of what's going on, and how to fix it? Thank you for help.