RO water and CaMg+ = high ppm and low ph?

I have crazy tap water, measured last night at 660 ppm / 1.0 ec and ph 7.0.

Water company has 2 sources, nor cal water and local wells and it constantly changes the mix so I never know what I'm gonna get. Often the ph is over 8.5.

Using a RO stealth 100 the ppm drops to 10.

Adding 5 ml General Organics camg+ gives me 360 ppm and ph of 4.2.

Couple of questions:

camg+ recommends 5-10 ml per gallon. Isn't 360 ppm way high? I can use 2 ml and get around 150 ppm but I'm not sure if that's enough calcium and/ or magnesium.

What's causing the drop from 7.0 to 4.2?

tia

Different salts effect EC differently. The conversion from EC to PPM is really not much more than guesstimate. You sound good to go imo.

If you are positive your pH meter is reliable, then I'm interested in knowing the pH after mixing all your nutrients.

cal and mg are both alkaline minerals. It is a large drop in PH but it doesnt surprise me.

i just fed 2.5 gal of RO water (less than 10 PPM) with calmag+ from botanicare at full str 5ml/gal ppm was ~310 at 5.6ph if that helps u at all for reference.

purplehays1 said:

cal and mg are both alkaline minerals. It is a large drop in PH but it doesnt surprise me.

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Wouldnt that raise the ph then? I thought low numbers meant more acidic.

lol ya u are absolutely right i mixed it up. Counter intuitive actually cuz those minerals are alkaline, but the solution must be acidic. Wierd. Ive actually found everything i give my plants i acidic, i have a big bottle of PH up but no PH down, never needed down.