2 the guy with the 150 ppm,its perfect.less calmag less money spent.heres the dealllllll,ive worked many trades,now i currently work with hazerdous waste water treatment and de contamination.if your water is sitting inside and your ppm ration is elevated it is because your water is evap faster than the chem's,this has been stated several times.there are only several thing that break down metals,chemicals,and v.o.c's this is natural sunshine.the sun light will break down molecular structures of almost anything that it comes in contact with,u can put motor oil in the sun and if left long enough 90% of the liquid that makes it mushy will evap and leave behind a cookie doh like substance.just having a bucket or a 40 gal trash can full of water in a grow room isnt going to cut it.usually one of the only chem's that will be released before vital minerals and metals break down needed to grow plants is chlorine and organic vapor. both of these things will harm plants,but leaving your water out to long will only cause problems....