Toppin off my buckets

im currently running some DWC buckets, my question is about toppin off. i have just been giving them fresh water with a PH of 6.8 as needed. is this wrong? should i be checkin my PH and tryin to use the fresh water to re-adjust the PH if it has dropped or spiked? which i like to keep at an even 6.0. should i PH the fresh water to 6.0 also? i assumed that the job of the PH buffers in the nutes was to keep it where it needed to be as long as i kept up on the water level in the bucket. little help please.

it's always a good idea to check and adjust your PH both before AND after adding it to the rez.
example: say your ph drifts up to around 7.0 If you PH your top off water to 6.0 and add say 0.5gal it may only lower your ph to around 6.5 instead of the 6.0 you're looking for.
at the end of the day, the only thing that matters if what PH your REZ is at, not the add back.

i check and adjust water that im adding in the res its just easier to me to do it right there in the container. then i check res as well make adjustments as needed.

thanx guys. luckily i havent had any problems yet, but i will definatly start checking before and after to make sure it stays where i want it.