I have an american plumber WVC34 two stage whole house filter (25 and 5 micron spun polyproplene filters), and the 25 gets pretty nasty looking after only 2 weeks. Tan colored deposits that mostly cling to the filter and start affecting pressure after 4 weeks. Is this fairly common? I have a 120' well that goes 110' into limestone and with 60' of 6" steel casing The static water level is around 20'. Well is about 30 years old and originally produced 25gpm. 1/2hp subersible pump. The water at the tap is clear, but I'm just trying to get an idea if it's an issue. I'm likely going to get a new pump in the next year or so and want to know if the installer should be looking at adjusting the pump height.