Instead of doing that, I make my solution 12 to 24 hours in advance. I no loner adjust PH for at least 6-8 hours after mixing the solution. I find the PH rises the longer it sits in the bucket for at least the first 2-4 hours. I also now use a fish tank heater in the bucket and bring the temp up to what it would be in the res, 70-72F. Then I adjust it as needed and let it sit another 4-16 hours for a total of 24 hrs.. I've found that my ph stabilizes and doesn't need another adjustment in the res. I haven't check PH in the res in over a year without issues by doing it this way. Doing it this way prevents PH fluctuations in the res.