I use RO water that comes from a water store. I have never check its PPMs myself but the guy a the store says it is 3 PPM. Now that I purchased a PPM meter I can check myself.

After the flush the plants still seem to be showing yellowing on the tips of some of the leaves. However it is hard to tell if it is new yellowing or yellowing that was already there.

On the other hand, the bud production seems to be very nice. Especally since the CO2 has been going. The pistils are looking white and new ones are developing everyday. Overall the plants look good and only about 10-15% of the leaves have yellowing tips (I'll post new pictures tonight).

My new plan is the check the PPMs daily and see weater it goes up or down like this quote from a grow FAQ:

"Start with 1.00 EC (or a SAFE nutrient strength). Next day, if it reads 1.4, it means your plants have been using water and your nutrient solution is becoming more concentrated. This means the concentration of nutrients is too high, so you dilute.

If the meter reads lower than the previous day, 0.7 say, it tells you that the plants are eating nutrients faster than they are drinking water, so you should increase your nutrient strength. If it remains the same, your feeding schedule is on target for now. The nutrient/water intake fluctuates with the growth of the plant, so you must continually monitor it day to day."

http://growfaq.marijuana.com/growfaq/1248.htm

Does this sound like a good plan for me to determine the correct PPM to use for my system?

Thanks,

GrowerXLT