hard water...ppm/EC problem.....

hey,..i have a question concerning measuring the runoff after feeding or just watering....
my question is this....

air inducted to change out room air at 3 mine or less
10k lights
have hard water, out of the tap the ph is anywhere from 7.0 to 7.8, it varies from day to day. the ppm is usually bout 270 to 320, so fill 30 gallon up, and ph down to 6.0.
ppm is at 270 to 320( varies daily).
ph at 6.0
ec is at .46
next i add 75% of max nute recommendation(4th week of vegg),..and i worked up to 75% from 50% starting out...
after i add nutes,..ph down to 6.0..ec is at 1.7 to 1.8
however,..now my ppm is like 1600 to 1800,..i think this is way to high ppm...so....i check runoff,..and its like 2000 ppm,..way to high im thinking..
the ladies look ok,...have been growing steady,..but now they r a little bright greener then i like at the new growth....

so wat do i do?..im using technafloras recipe for success,..at reduced amounts,..and am using a feed...water...water...feed cycle...
my understanding of this is that the ladies r drinking,..but not really eating that much,..according to measuring this runoff(i water till bout 10 to 20% runoff)
so i last fed at bout 5 days ago,..and have watered once with some spot watering going on,..still the ppm of runoff is 1t 1670 this morning,..ph is 6.1 ec was at 2.46
isnt this way to high ppm and ec?,..wat to do?.....i have only 1 grow under my belt,..i read 10 to 12 hours a day,..google everything but still,..there is no replacement for experience//
would apreciate some help from u guys or gals,..ty....peace!

Quoted from weedfarmer.com

"If the starting water is above 200 ppm, that is pretty hard water, that will lock out mg with all of the calcium in the water. Either add a 1/4 teaspoon per gallon of epsom salts or lime (both will effectively reduce the lockout or invest into a reverse osmosis water filter."

JSG.

ok,..ty for ur response....so since my ppm is already over 270 at the tap,..ur saying that its locking out mg..but what do ya mean with the..(and all the calcium in the water) part,..r u saying also that the calcium is also being locked out along with the mg?
please be patient as i am very new to this type of growing and horticulture,..am just trying to dial this in so these ladies r happy,..as well as the patients who depend on me for relief.....

the reason im asking this is because my new growth is bright green,..and im not sure if this is a nitrogen deficency or mg/cal problem,..because im just now seeing these growth stages for the first time,..my ph is right at 6.0,..got my ppm down to around 1200,and the EC is at 2.0 now,..i been flushing without epsom salts,..but adding a little hydrogen peroxide,...then ph down to 6.0,.and just flushing,..they seem to be responding as they r getting a little better looking as each day passes,...what a learning curve!,..lol... repotted sativas,..into 5 gallon.....looked at the roots,. and they all looked really healthy so far,..might just leave the indicas in the 3 gallon pots as they wont get near as tall.....cant wait till i have alot more hands on with these problems that arise in these ladies,...peace!