PH adjustments in RDWC

Hello my fellow Hydroponic growers.
I am getting setup for my next grow and you all have been great help in helping me learn the art form and I appreciate that.
As I sit here thinking about the issues I have had during my first grow, I am learning to make everything simplier and more streamlined.
One problem I came across and not sure how to do it correctly is adjusting my ph.
So when I do my weekly water and nutrient change I ph the water after my nutrients are in then I pour it into my reservoir where it works its way thru my 4 grow buckets.. And everything is well and good.
Now my question is how are you guys adjusting the ph after.
I know I can check my ph in my reservoir and that will basically give me the ph of my 4 grow buckets,
Now what I dont understand is if I add ph up or down to my reservoir. How am I getting a acurate reading of my ph in my grow buckets. would i be adding my ph up or down slowly and have to wait for the system to completely recirculate, and add as needed. That seems like it would and could take a lil time.
Now I am not being impatient if thats the way to go then thats what ill do just seems like there should be a better way.
Thanks in advance for all your help

I've only got a couple rdwc grows under my belt, but basically start recording what you are doing. I do the same thing you do, mix my nutes then put them in the system. I start at 5.5ph and over the week, it climbs to 6.0 or 6.1. I do have a top off rez and I ph that ro water to 5.5 which in theory helps keep the ph from rising too quickly in the system itself. My 10 gal top off rez filled with ro water requires 2ml of ph down to get it to 5.5. Now I know this after repeating the process and measuring each time to confirm. If I need to add any ph down to the system itself, say the ph is 6.1 and I want to bring it down a little bit, I'll add 4ml ph down to the control bucket and it will bring it down to about 5.6-5.7 (28 gal system). I'll say it again, write it down. You are correct that when you add to the control bucket, you do need to wait awhile (depending on how many gph your water pump is) to get an accurate reading for the entire system, that's why if you record the beginning ph the amount of ph down you use and the resulting ph, you will eventually know exactly how much you need to add based on the current ph reading. Once you are comfortable with what you need to add, it never hurts to take a measurement afterwards to double check your accuracy. We're stoners, shit happens. At this point, I just ph the top off rez to 5.5, start the nute system at 5.5 and don't really add anything during the week before I change out the water again. Every day at lights on I measure the ec and ph and record it. My small 6 site (7 w/ control bucket) is drinking about 4-5 gal per day, top off rez is a good idea and cheap.

Are you running a sterile system or using beneficials? Are you chilling your water at all? Looks Nice!

I add slowly, recheck as needed. Some systems are bigger than others.

Thanks guys.
So Ill keep careful record of what I am doing to adjust the ph. And at one point things should be consistent and Ill get the rhythm..
Patience I get it lol.....
Blackforest.
I am using good old 2 litre frozen bottles I swap it out every few hours. Saving the pennies for a chiller but as of now frozen 2 litre bottles are doing the trick.
I have yet to decide how I am going about this grow as far as nutrients etc.
Right now I am thinking Ide like to keep it as simple as possible
I was looking into advanced nutrients Ph perfect grow micro bloom and then using something like humboldt's golden tree and just use those threw the whole grow to keep it simple. thoughts?