I have a shallow well with 2" pipe coming out of the basement floor. This pipe is encased by cement, then has a check valve right before a 90 degree elbow. I believe i have a lime build up at screen, have replace with a new 1/2 hp pump already and no change.....How can i clean that screen? the pipe is old and rusty and don't have a lot of money to replace well. Could i cut pipe before checkvalve and drop the nu tablets in and if i do how would i get a prime back.