Chlorine and well water; HELP ASAP

I just found out that my city water supply has chlorine in it, which should not be a problem since it is low, according to them. But I also found out that 1/3 of the water is from a local wells near agricultural farms. I have a big res tank and am dependent on using the city water without RO, just can't afford it right now. Does the well water pose serious issues since the city did say the water supply is susceptible to contamination? I was going to just get a big barrel to let the water sit to evaporate the chlorine, but now that I am aware of the well water issue, I don't know if letting it sit would help. The ppm is 190, ph around 8.0. The issue came up because I keep getting bad leaf issues that look like golden/rust spots that are starting to get worse now with some drooping/dying ends of tips leafs. I think it's Mg deficiency and added some epson salt two days ago. I'm using a flood and drain in hydroton medium. I'm only in 20 days from seed. I already added some epson salt 1/2 tsp x the number of gallons of my res. and have some CaMg+ that I can add any time.

All municipal water supplies are chlorinated. No biggie. Just drop a airstone in a bucket of water and bubble it for 24 hours. The chlorine will evaporate. If you are going to use well water you should get it tested first. It is almost always loaded with dissolved minerals.

I suspect that the spots on plants are caused by bad feeding. you can use a low dose of H2O2 (non-chlorinated bleach) to prevent contamination