Using different hydro solutions on same grow

Is it OK to use different makes of hydro solutions in a grow? I know it's probably not the best idea, but I live in a country where it's very hard to get these solutions past customs. I have to order from different suppliers around the world and pray.....

So far I managed to get 3 bottles of formulex in, which I will use for the seedlings when they're 10 days old. So will probably run this increasing strength for 2-4 weeks, then move on to a grow solution and finally bloom.

I'm just wondering if it will affect the grow much, or if all these solutions are pretty much the same?

i live where hydro is not common and i resort to diy, buy ferts in parts, calcium nitrate potassium nitreate potassium phosphate and magnesium sulfate + trace element mix, that would be good to start. phosphoric or sulfuric acid h2o2 and such are sold for various uses so you must be able to find them