Water Softeners and Air Filtration Systems - regeneration problem

the system i have is a 2 tank system, 1 tank is for media 10 +54 vessel with electronic head /timer the other tank is hooked up 2 a air compressor, i do have iron in my well water the problem is that when it regenerates the media is disappearing the system has never done this before, i have owned the home for almost 6 yrs this is the first problem that i have had with the system ,my water guy tried to take the top off the tank to look at the tube inside but could not get the top to turn so he just looked inside to see if the tube was ok, is there a trick to get the top off the tank to replace the tube or do i have to buy a new tank, the backwash line is hooked to the side of the valve and that goes to a dry well outside, there is no media present in any of the aerators at the sinks ,my water guy said that the media is probably going out to the dry well.[system hook up] the copper pipe comes from the well tank 2 the tank that is hooked 2 the compressor from there it is hooked 2 the bypass valve on the in flow side of the media tank ,then goes to the house from the other side of the valve ,shut off valves are on both sides of each tank and backflow/check valves are in place. any help in this matter would be greatly appreciated. thanks to biermech for the response to my early post.

Is it possible to post pictures? If you are losing media through the drain, the only thing I can think of is the air is not being despenced before the mrdia filter. The air in the media filter could cause it to raise up too far and exit the drain.