some basic hydro questions

I plan to switch to hydro but I am confused as to how to feed them. Do I put the nutes in the res for 3 days then switch back to clean h2o? And do hydro plants stay shorter than soil grown plants?

There are different feeding methods but basically the nute level rises until then end when you flush with plain water. Best to pick a good nute product and use their feeding schedule. Hydro won't stay shorter than indoor soil but shorter than outdoor soil, yes.

So I keep the nutes in until the last 2 weeks?

im growing in hydro and i dont have my ec tds meter yet. i have learnt the hard way because of this. i top my res up daily with balanced water due to having only a small setup my ladies are now drinking about 3.5 litres daily so just over a litre per plant as only got 3 left. i was being a bit over zelous on the feeding when they were young and lost 3 out of my original 6. i feed them every other day with 2.5ml per litre of the tank and they are blooming bueatifully right now.if switching to hydro grab yourself a good tds/ec meter and you can see exactly whats in your res and know if you have to adjust it up. hope to have helped dude.

some people feed right up till the end some people flush 2 weeks before for a cleaner taste to the bud, but most strains gain alot of weight in the last 2 weeks of flower so it seems kinda dumb to stop feeding?? but im new on my first grow and have no comparisons to tell you so cant say for sure which is better.i think i might just flush with water in the last week.

So in retro spect; where do I start. Lets say I buy 2 drip units. 1 for each stage. Do I leave the nutes in the res the whole time and just monitor the ph balance? Also how in the hell do I trach a post?