Adjusting water ph question

Noob with a question about adjusting pH of my well water. Untreated water directly from well (unsoftened) is coming out at 7.2 pH. I am adjusting it one gallon at a time. Used pH down and got the water to 6.5. Checked the leftover water in the gallon a couple weeks later and it was back up to 6.9. Is this normal as the water sits, or am I doing something wrong?

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Do you have a TDS meter?

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You should get a good TDS/EC meter. You will need to watch values closely. Your dissolved solids could be high. You will need to correct or compensate based on true values. Best of luck on your grow. :+1:t2:

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Adjusted water will drift back. Only treat what you plan to use immediately.

Yes, pH drifting upward is normal after pH adjusted water/nutrient solution sits for a while. BTW the upward drift is actually a good thing when it comes to nutrient uptake. Some nutrients are best utilized at the lower end recommended pH range for a given medium. As the pH changes upward other nutrients are made available to your plants. As an example, I grow in coco coir which has a generally recommended pH range of 5.5 to 6.5. After I’ve added nutrients to water (R/O) I adjust the pH of my solution to 5.7/5.8. Turns out that manganese is best utilized at around my pH starting point but falls off from being utilized as the pH drifts upward toward 6. But calcium and magnesium only begin to be utilized as the pH approaches 6 (and higher). Other nutrient compounds such as nitrogen are absorbed/utilized throughout the pH range.

As previous commenters have suggested, get a TDS or EC meter to get a handle on the dissolved solids in your water. I have very hard well water which is why I use reverse osmosis water as a starting point.

Thanks for the quick replies. Was not aware that it would fluctuate back up. Will only mix small amounts from now on. Thanks again.

I second @howill answer. Nice small fluctuations helps diff intakes. Wheres my chart…