Water PPM question

Hi there !
If my tap water is 100 ppm before I add the nutrients ,and if I want 700 ppm like it says on my chart , do I include that 100 ppm or not ? Or do I need to mix till I,m at 800 ppm ?

Thanks

Boris

The 100ppm must be accounted for.. So add 600ppm of nutes.

Well it all depends on what makes up the dissolved solids. They're only going to be trace elements. It also depends on what's in your nutes. Not all nute are created equal. Even if the ratio on the front is identical. Look at the ingredients. To do it right you'd actually need to search water tests city water gets tested often and the results can be found. Some nutes lack essential elements and the grower never notices because it's in the tap water.

If your nute line has cal/mag you might not need it. In which case your PPM will be lower.

Monitor your tap water regularly, it might not be consistent. We used to have really good, stable water, then they started replacing water pipes. Now, my towns water fluctuates day to day. The other day it was 0.8 ec and 7.0ph, yesterday it was 0.3 ec and 8.0 ph.
I don't use it anymore, I went RO because of that. All it takes is hydrant flushing or construction work and your water can get messed up for a couple days to a week from everything in the main getting disturbed.

Most public water supplies are going to try to maintain ph above 8.0 to reduce the problems flint had - leaching lead from pipes. They do that with salts. Try to get an analysis of your water. You may find a lot of calcium and potassium in that 100 ppm.