would it be a problem to change the nutrient family in the first week of flowering?

You can change your nutes any time you want and I have done... so I'll agree with creepy_steve here... but as I told you in one of your last questions, the brand of fertilizer has nothing to do with how your product will taste. None... unless you use chemical nutes and don't flush AND have super-sensitive taste buds. The taste and effects of your harvest will all depend on a) when you harvest and b) how you dry and cure. The only reason I chose to "change horses mid-stream" was because I was having lots of toxicity and deficiency issues with the nutes I got rid of....

hello 😀 if you want to use advanced nutrients I would recommend to download BudLabs app Best Regards 😎

you can change product at anytime.. no worries you won't cause some poisonous gas or an explosion or anything :P fertilizers, which some components have various options, are still made of ubiquitous commodities... if there's a concern it'll be clearly labeled what not to mix it with. in my experiene with "marijuana" brand fertilizer instructions, they instruct a very high dose so that you buy more of their watered-down fertilizer at a more frequent rate. use your experience before.. .compare the weighted average of N/P/K/Ca/Mg/S percents off labels and relative to dosing ... if it's similar to before, you'll have similar results. if you didn't hammer out a formula that kept a plant healthy from seed to harvest, you'll still have some trial and error to figure it out... observe and react.. take notes... do better next time. the brand isn't the key.. buy cheap fertilzier. premium pricing just equates to an e-peen. If you ahven't bought it already... do someting different than AN.. they have some predatory business practices that show they have no respect for their customers.. you have to buy a bunch of supplements for no reason. it's pretty expensive when you add it up per gallon mixed. it's not ph-buffered... it's just not a very good fertilizer. They have neat cartoon labels like sugary cereals in the supermarket to attract certain people, LOL :P