I don't think you would have a problem, since they are going after different things. You could consider alternating them every other day, or when ever you dose, if you want to be a bit more careful.
However, before dousing anything, first make sure you actually have a problem, and second make sure you have exhausted other means of controlling nitrates and phosphates. By having a problem, I'm talking about something like really excessive algae growth that can't be controlled by the usual means of cutting back on feeding, more partial water changes, filtration system upgrades and so on. A higher reading than you would like, by itself does not necessarily indicate an issue.