I'm coming into my first week of flower with ...

The plant needs mostly the same proportions in flower. Maybe 10-20% less on N if you were feeding ~120-130ppm before. If feeding higher, you likely have even more built up in the leaves and can drop it a bit lower. soilless growing, whether coco or not, is simply maintaining critical levels of nutes around the roots. A consistent equilibrium forms if you are religious about 10% runoff waste each fertigation. Always fertigate every irrigation, too. there are apps that can calculate and total your PPMs from your guarnateed analysis labels and dosage of each. Or, tracking your weighted average ratios of all of then - NPK as well as Ca, Mg and S. Watching this over time can be very useful for adjusting your formula to the point you rarely see even the slightest nutrient symptom in your leaves - and it will work for 99% of plants that way, too. Once you have the formule worked out in a way that works for 99% of plants, it's rarely even a concern in your head. Simply apply and expect great results without worry. Fertilization should not be a major concern after a few grows of paying attention to these things. After that, you don' have to do it. I'd suggest soemthing like this for mature vegetative plants, then take N down to 100-110 AFTER 'vege' growth ends -- vege growth = leaf growth and stem elongation, which continues for several weeks after the plant, photoperiod or not, flips to flower phase. N 120-130 P 40-60 K 180ish Ca 100+ Mg 75ish S 100+ your local tap water may impace some of these values. These values are not mean to be EXACT DO OR DIE!!! lol.. but more of a ballpark to start in and have minimal adjustments necessary. This is only 1.3 EC (on 500 scale)? It's a very low starting point. Depending on local vpd you may need more... if you add co2, you will need a higher concentration, too. More than one factor is at play here, so you simply observe and adjust to what you see occurring with the leaves over time. When your formula is good but not great, you'll still have buildups or deficiencies that take several weeks or even a month of more to see symptoms. The slower the progression is, the smaller the adjustment needed. Everytime i've experiemented with more P or more K or drasticalyl shifting N in flower, while all other factors are reasonably the same, i only start to see problems develop over time. It's a myth that you need to amp up P or K in flower. simply bro-science. The changes needed to maintain a super healthy plant in flower are not drastic. don't beleive me? go do some research. you'll see yield and potency in numerous 'real' research done by trained professionals shows there's no impact to gassing either of them. I've been testing boosting P for last 2 years (also, not adjusting anything else in formula) and it's just a lot of extra effort with no return, lol. I'll humbly be reverting those changes heading into this grow season. the more research i read helps make that decision easier. Was just a self-absorbed thing that made me feel like i did something helpful for the plant, but really didn't do shit, lol. Understanding how the plant takes in minerals is helpful too. "Mass flow" or "active transpot" takes care of 99% of it. Mass flow lets anything that fits in (diffusion) but active transpot is a selective process and the plant only takes in what it needs. So, the key is 'critical levels' of nutes that exist around the roots at all times for best results. It's not the ratio at which the plant uses them (my initial perception too) but rather the ratio that allows for greatest availability of all minerals physically present around the roots. This does not match up with how it will be used in the plant. It merely maximizes best results of active transport. Each time you give 10% runoff, you reset that equlibrium back to where it needs to be. I've only learned that in the last 6 months or so. Trial and error gets you to teh same point, but i would have gotten there sooner had i known this 5+ years ago.

You need Base nutrition. If the company does not make a base nutrition for flowering, then you would continue to use your current nutrition. Just adding a bloom booster for flowering on top of it.

We don‘t know what kind of nuts you are using but normly every nuts brand provide nutriens for growing Phase & flowering Phase. Stop the growing nuts when you swich to flowering nuts, otherwise you will burn your plants of you use Both, but again it depends on the nuts you Are using as the instruction manual of the Company