I have always been curious because Advanced Nutrients says you have to use __ML every week, like every week you have to change the water or something odd like that. I always thought you added your nutrients everyday until the PH was right, and that's about all it took. 2nd Question: A lot of people say I need a water cooler, what temp should the water be at?
your mashing a few things together, and all nutes work this way, not just AN some mix a fresh batch of nutes once a week and top off each day with water... then a week later they drain the system and start over others mix nutes once a week... top off each day with water then a week later they take PPM readings and figure out how much nutes to add to bring the nutrient levels back up, called add back AN specifically states that you should drain to waste if im not mistaken... but many have stated its so you use more nutes and thus give AN more money... for me its just easier to drain to waste so there is no guessing on my part with math... but it is seriously expensive to do things this way as far as soup temps... the cooler the better, but at some point your res will start to sweat... 65-75 is average... my personal opinion is 68... but that works for me... you should find what works for you, but more oxygen is present at lower temps... so cooler is better, but too low and that causes problems... so the the trick is looking for the sweat and raising a couple of degrees good luck
Mix your nutes with water and add the mixture to water in your res (in the proper order) and check the PPMs and PH. If those levels are where you want them then just add water to top up the res every day or so. At the end of roughly a week. drain the res and start over. I like my water temp at 60 - 70 deg to keep algae etc away.
The only time I change the water in my rez is during my 10-14 day flush at the end of flowering Unless I have some type of algae issue or something the water stays I only top off with water and add nutrients weekly
i persoanally add my nutrients whilst tank is filling with water, always put same amount in and adjust at the end. ph etc. every night when lights are on i check my ec first, ppm i think you guys call it then adjust ph with up or down and thats it. but change water every week, it may cost money and i use canna products at all times. i will be doing a full grow journal starting in about a week so everyone can see properly with pics etc. im from australia so a few are diffent that im slowly working out.
I do a soup swap once a week. Experience has helped me with how much I have to mix up for the correct ppm, and I check it once in a while, but I don't add anything after the swap. A float valve keeps the soup at the right level. This is fed from a 4 gal R/O reservoir.