You shouldn't purposely use all 3 at once.. that will assuredly cause an overdose of some sort or unknown chemistry that could wreak havoc.
if you must, use one up, then move on. maybe to be safe, give a water only irrigation or two between. if they are complete feeds, you'd be double dipping too much on too many things that overalp. find a good system of products that provide everything at the proper concnetration and proper ratios.. don't want to do the math? get a 3-part system like jack's. can make minor adjustments to various parts based on how the plant reacts. has all the micro and macro nutrients plust trace elements.. no guessing. more certainty. doesn't have to be "jack's" .. can be anything similar that's cost-effective and available locally.
their website gives the elemental ppm break down of their product when mixed at their instructions. from what i know, our particular plant of focus needs slightly more P than they give, for example. But those concentrations and ratios would be an excellent start based on science of people more educated on the subjects than us.