Bubbleponics PH levels

Ok, this has probably been discussed before, i'm 10 days from sprout. 6 gallons of water(city 7.7-8.0) is ph adjusted, nutrients added(Stealth Hydro), and poured into the resevoir. 12 hours passes and the ph of the solution is tested, it reads 7.4-8.0. Now it needs to be adjusted again. It is still approximatley 6 gallons, now my question. I know it's written to not adjust while in the res, so is it drain the res and ph adjust the solution and replace or drain some of the solution and ph adjust it low(4.0-5.0) then replace aiming for 5.5?
I guess i'm asking what are your best methods for ph control?

usually I just take out a gallon and over adjust it then add it back. remember to not try and adjust alot over a short period of time it can possobly cause root damage. also when I adjust I usually give it an hour or so before I check the ph again. that will give your solution a little time to completely balance out.

Using tapwater,your water has a ppm so it will rise.Mine is 7.5 and i lower it to 5.0.I wait a day and its risin to 5.5-5.6.Exactly where i want it.Then i add the nutrients.I gotta use 5ml/down per gallon to bring the ph down.

If you use RO water,it takes a small drop of ph down to bring it crashing,and the ph doesnt rise cause it has no ppm.I suggest using that kind of water.But any water will work if used correctly with proper nutes

If your roots are not in the res yet - i.e. they haven't poked out the bottom of your netcups, then just disconnect the pump that powers the irrigation hub and add your ph down/up straight to the res. Let the bubbles mix it for 5-10 minutes and then check the ph again and add more if necessary or reconnect the pump if it is at the desired level. If the roots are in the res then your method is fine.

You will find that the first few days after a res change the ph will fluctuate madly - but after that it settles down and is easily managable