Virginia "Black Mud" from well - Silt management question
My house has a recurring sediment problem with a micro-fine black sediment that despite a number of efforts still infiltrates our house water system.
The micro-fine grit tends to eat up well pump about every 5.1 years (with a 5.0 year warranty). Last time we replaced the well pump, the well had lost thirty feet of depth due to silt accumulation over 18 years. Originally drilled at 395 ft, it now measures 365 feet, we pulled the pump up ten feet hoping to get it a bit above the grit.
Two years ago we installed a large Well Mate UT-120 pressure holding tank just down-line of the pressure tank that is fed from the well water line. Every month I purge 15-25 gals of black silty water from the bottom of this tank. Silt is noticeably more severe following large rains such as we 've had this spring.
From the Well Mate Settling tank we have a RAIN SOFT water treatment system with two large tanks that back-flushes each early morning. These tanks have had to be replaced in the past when they filled up with black silt and wouldn't function.
http://www.sutton.org/images/SiltSediment002.jpg
I have a 5 bedroom, 5 bath house that now has 3 people living at home. Next Fall, one daughter leaves for college leaving two of us here. I don't know what gallon usage that represents.
Having watched most of the videos on the site, I am thinking of the Big Blue 20" filters. I am wondering whether one BigBlue20" would suffice, or if I should install two units in-line with medium and fine sediment filter stages.
I would appreciate advice on this problem and solution choice from anyone.
Thanks in advance.