Understanding how to correct my food/water

Hey im a little confused on topping up my DWC buckets with nutes and water with working with EC / PPM. Ahead is waht ive added and what im at now.

Im at my first week of flower and into DWC system And what im using is:

Canna FLores A+B ( 21-13-27 ) - 45ml [ 2.5-3.5 ml/L ] With and EC of 1.2-1.7 Bloom Stage one.
SilikaMajic (0-0-15) - 5.3ml [2-3ml Per 10L ]
CMX ( 4-0-0 ) - 9.5ml [0.5m/L ]

Each bucket had 18 Litres of water and this amount of Nutes and additives. With a Ph of 5.5-.59 And a EC / PPM of 1.2 - 600 I was trying to aim at 1.4-5 but i didnt know how much of each nute and addi to add.

At the moment each bucket has drank 1-2 litres and the Ph is around 5.4-5.9 its ok and the Ec / PPM is @ 1.0 - 500 in all buckets.

My brick wall is here. At the moment How do i know how much of each nutrient / Additive i should put into the water to raise the EC /PPM upto 1.4-5 -700 to 800. (or even do i need to add the 2 litres of water back?)

Even when i make a fresh tub adding the nutes and additives recommended by the bottle, I got a 1.2 EC Reading. So how do i know how much of the nutes /additive i should add to raise the EC upto say 1.5 without over dosing on different elements.

Is there a formula i can work with or way i can math this out?

This is where im soo stumped grrrr.

its best to use nutrients for a week or 2 then use fresh because the plants excrete waste back into the system. any concentrated chealated nutes or basil salts are the same doesnt matter what brand.

Well what i thought was the right thing to do during the week if the plants drink or eat too much need to top up the tup with either water of food.

if you ever do any topping up i would only use water as there is no accurate way of telling whether the ppm represent the nutrients levels or the plant waste levels, i guess if you where to calculate to expect half of the current ppm after a week to be plant waste you could base adding nutrients on that, so like half dose or 1/3 dose every week as a top up and then an actual water change every 3-4 weeks but not recommended imo

righteo mate cheers i will take that into account