Quick question on tap water

YUP, but after 7 years of use, my reservoir looks lethal, and I can’t transfer the water in reservoir, currently

General Hydroponics sells hard water micro nutes. Im sure other companies do as well. My well water is 300ppm+, 8-9ph out of the tap depending on day and i dont even use the hard water one and i’ve had no issues. I just use the ph down and nutes and going good so far in FFOF soil.