PPM Question

Can anyone point me in the direction a real good thread on PPM. I have found charts that tell you where your PPM should be at different stages. The thing is my water is 380 PPM out of the tap and I do not know if I should subtract that 380 from my current PPM. If not it seems like it is going to be real tough to stay within the recommended PPM's. I am using a Hanna TDS 3 PPM checker which has a conversion of .5

You are generally supposed to add the correct ppm + the ppm of your water.
So if you are going for 1000ppm you would have a reading on your meter of 1380ppm when all nutes have been added.

Try putting your tap water in a bucket and let it sit for a few days it makes a difference for me.. usually lowers my ppm to start by 100... PEACE

if you get yourself a r/o filter, you can feed more nutes. if you're ppm out of the tap is 350 and you feed full strength, you can burn the plants. get yourself an r/o filter.