Mix 2 types brands of nutrition?

Totally yes. More so organics can be mixed pretty much however u like within reason as they are slow acting organic products all mixed together anyways. Synthetics can be, less happy to play well with others but in weaker doses they are far less likely to react with each other. Diff brand boosters also tend to work well with other brands main nute lines too, if used on their own at the right times. As long as u dont mix them all up in the same bucket, u shouldnt have an issue. I use lots of diff nute lines and as long as im careful not to start adding too many things all at once, its always been fine.... more so if i did have an issue bad enough I even thought about mixing bootsers and nutes and a bunch of other additives together to try and fix my plant or make it grow "better", well that means im doing something basic wrong and need to fix that not start looking for a fix in a bottle.