Tap water - Chlorine / PPM / pH

[GregoryJ]

I'm working on growing some lettuce in a NFT system with 4" PVC pipe. My problem is when i change nutrients, I have a difficult time maintaining pH for the first couple days. The roots turn brown, growth stops. Finally get the pH corrected and the new root growth is white, and the lettuce takes off.

I'm wondering if the local city tap water has too many... chemicals! and this alters the pH or damages the roots? After a couple days, pH stabilizes and root growth is good... maybe after the chlorine in the water evaporates?

ideally, I would use a RO system to clean things up, or buy distilled water and add in nutrients. But for now, its just tap water. I use tap water to water my tomatoes and other plants - but they are in soil. So, how much does the - chlorine/flouride/??? whatever else is in our tap water - affect the plants? is there anything to use to neutralize the chemicals in the water - like "start-Right" for fish tanks?

Thanks.