since you are committed to buying and building a good system, you should buy an r-o unit to distill your own water

tap water is around 200ppm's...mine from my deepwell is 163-187 depending on season
after running through rodi unit, I have 003 ppm's...so you see, you draw water,test it,
now you know what your natural ppm is...then add nutes and test it, this is your ppm's with nutes added...then check your ph. Alot of nutes have built in ph buffers and sometimes i get a perfect 5.8 ph reading after adding base nutes...hope this helps,
there is alot of good help here, sorry if I reiterated anyone else's advice, but I came to a point reading this thread that I said...this is what my man needs to know. You can use your tds pen anytime you want. It is for telling you the strength of your nute solution, plain and simple....good to see all the healthy responses here...lw
latewood Reviewed by latewood on . HELP ME PLEASE!!!!!! Using this system Caddy Turn Key System http://www.sunlightsheds.com/cool_cab.htm Using a 17gal tank to hold the water. Using Rapid Rooter Natural Plant Starter for growcubes. Also using Hydroton Clay Pebbles. For nutrients using EcoGrow "L" 5-0-3 (npk) (part A) & EcoGrow "L" 3-4-5 (npk) (part B). Also have Supernatural Excellofizz http://www.ecogrow.com/index.cfm/product/639/mid/16/nid/0/home.html Also using Hydrofarm CO2 digital Tester. Genesis Solutions Standard Solution Total Dissolved Rating: 5