Ro Water Troubling Calcium, And Plants Started Showing Deficiency Symptoms.

Hello,

Ive started using complete 100 % RO water because the water we have here is no less than liquid metal.
RO Water KH is 0 and TDS is around 110-120.
400 L tank capacity

I dose DIY fertz but 2 things are causing trouble

1). Calcium
2) Traces like Chloride, Nickel (No such deficiencies i could detect so far, but its expected in a long run)

My Nitrates are around 20ppm (may be 25 ppm at Max).
I'm using EDTA-Mg to dose Magnesium but the real problem is with Calcium.
If i use Calcium Nitrate the Nitrates are Exorbitantly high may be by week end it reaches 80 ppm
Calcium Sulfate - Not at all soluble
Even if i use Calcium Chloride the Chloride will go as high as 26 ppm that too PER DOSE...

RO Water

pH ~ 6.5
Nitrate- 10 ppm
KH - 0

Other fertilizers m using are (All as per EI)

KNO3 - Nitrate skipped
K2SO4
KH2PO4

Ca (Troublesome)
Sulful (no Separate dosing)
EDTA-Mg
EDDHA-Fe
Micronutrient doesn't contain Cl & Ni)