Thanks - doesn't seem to be available in the US though. Also I noticed that it contains potassium carbonate - for me it seems risky as it might have a negative effect. I would probably opt to go with something like this:
That way, with the liquid zinc and powder p5p, we are not adding anything other than zinc/p5p.
However if you decide to use it, this is what I came up with:
The formula asks for 150mg of p5p and each drop/serving has 0.848mg of p5p --> 150mg/0.848mg = 177 drops
The bottle has 100mL and contains 1333 servings --> 100mL/1333 = 0.075mL per drop/serving
177 drops x 0.075mL = ~13mL
Now if we have 25mL for the zinc and 13mL for the p5p, it comes out to 38mL total
So if we want to have the same 60mL as the original formula, we would only add 7mL of distilled water (instead of 45mL). This way each drop will contain the same amount of zinc/p5p as the original formula.