evandostert,

Do not know about the questions you asked but check your locality to determine if your water has chlorine or chloramine to purify water. Chloramine will not go anywhere unless you filter it out. I had to find out the hard way. Thought we had chlorine water and after getting my water test back found out that my city stopped using chlorine years ago and now uses chloramine. letting my water set out or putting the air stone in it overnight did absolutely nothing!! I do not do R/O I just purchased a 97-98% chloramine removal filter and so far so good.

DL

Agree with dancinglemons, but I would ask for a complete chemical analysis.
My tapwater adds ± 250µS. Need to take that into consideration when mixing nutrient.

I think I am gonna get an r/o system and just add cal/mag to my nutes. I just am getting started and managing to kill a bunch of basil.