each pump from the bottle is 1ml.
That doesn't matter. It is the total amount you want to pump in for each dose that matters. With a 500 ml bottle, if you figure you will pump in 5 ml, 5 pumps?, each time you dose the tank, then you want 100 times the amount of each dry fertilizer per dose in the bottle to be mixed with the 500 ml of water. Then your 5 pumps, if that is what it is, will produce a 5 ml slug of water/ferts, and the bottle will hold enough for 100 doses.
This works very well for the EI dosing method, because we have a table of the approximate volumes of each fertilizer to use for each dose for each tank size, measured in teaspoons. If that table calls for 1/2 tsp of KNO3, for example, per dose, you would put 100 x 1/2 tsp, or 50 tsp of KNO3 in the bottle to mix with the 500 ml of water.
The first problem you will run into doing that is the limit on solubility of each of the ferts in water. I am sure you won't be able to dissolve 50 tsp of KNO3 in 500 ml of water. So, if you need to dose 1/2 tsp of KNO3 per dose you will need to make the amount of water per dose be much more than 5 ml, probably more like 15 ml. Then the bottle only holds 500/15 or 33 doses, with each dose being 15 pumps, and you would put only 33 x 1/2 tsp of KNO3 into the bottle to dissolve in the 500 ml of water.
I'm probably just confusing you - if so, sorry.
EDIT: It just occurred to me that you may want to know how much KNO3, for example, to add to the bottle so one pump increases the ppm of KNO3 in the tank by some specific amount. That isn't hard to figure out, but my brain is telling me to lay off this stuff for now, so I will let someone else figure that part out.