Island house help

[nhjenny]

We have a house on Sleeper's Island and are having water pressure issues. We get our water from the lake. have good pressure in the tank (Well-Mate), but then get intermittent pressure inside the house. One minute its fine, next its almost a trickle. My husband reset the pressure range on the tank, seemed to improve briefly, but quickly back to where it was. The pump seems to be operating normally, we can hear it kick on and run when the tank asks for water. Does anyone have experience with this type of problem? Wondering about the air bladder inside the tank?

Update: We just checked the sediment filter that we replaced 2 days ago and it is completely clogged with sludge already, even though lake water is crystal clear. This has never happened before. Does anyone have experience with this? Trying to sort out what is happening. Changing the filter again fixed the problem, so the pump and tank are fine. It looks like the tank is in line before the filter. Is that normal and could the tank just be full of gunk? Any ideas or info would be helpful. We are only on our second season, figuring this out as we go along.