How long till water goes bad

I’m growing one plant which happens to be the first. When I started watering 12 days ago I took a clean 5 gallon bucket and put 3 gallons water with cal-mag, silica mixed in. Ph was 6.80 first day I mixed which was 12 days ago but today it was 7.44 and I did correct that but it made me wonder. My question is how long can I use this water and will it go bad ? I shouldn’t have it much longer but I do still have some left. Thanks to whom ever takes the time to answer this question.


It’s best to mix nutrients immediately before feeding. pH will drift in pre-mixed solutions.


I noticed this same phenomenon. I read that water wont hold its pH unless its 350 PPM or more but it still drifts regardless. Also pHed water will still take on the pH of the soil i read also…?
Could somebody explain the science behind this? I’m pretty sure @MidwestGuy has knowledge on this… thank you


It’s pure water (rain, R/O, distilled) that will take on the pH of the medium you add it to, because it technically has no pH when the EC/PPM are close to zero.

Once water has enough mineral content to actually have a true pH reading, then it will have an impact on the medium you add it to.

A lot of people get stuck on understanding that pure water has no true pH reading. If you put a pH pen in pure water, whatever numbers it’s showing you are erroneous, and if you leave the pen in there you’ll see the readings changing, because there’s nothing for it to truly measure.


How about Tap water with 180 PPM, will it impact the pH of the soil or take on the pH?

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pH drifts in standing water whether it’s a solution or not. Also, pH changes when you send it through a tap, then changes again when it sits. I think people greatly underestimate the fluctuation of pH.

CO2 is acidic, (think: acid rain - apart from the industrial pollution kind). When it off-gasses from the water, pH rises, when it’s aeriated, it accelerates (airstone, tap-flow, etc). The loss is limited however, by something called Henry’s Law (just learned that one), which defines a correlation between atmospheric and liquid gas levels. (just mentioning for the occasional grower utilizing CO2)


180ppm is still pretty low, but probably enough to get a true pH reading. Once it has a pH, it will no longer take on the pH of the root zone.


Thank you bud… i have noticed that my tap water pH will swing if i let it sit out for a few days after i pHed it. I use a spray bottle for a Venus Fly Trap i have growing outdoors. When i pH the plain tap water down to 5.5 from 8.1 and let it sit a couple days it rises up to 6.5. So then i pH it down again and let it sit again a few more days. Then it dropped to 4.8… So after all this, i can see what your saying. A water with low PPM is unstable. So i add what i can to the water to bring the PPM up to around 400 if i am going to let it sit for awhile before i spray it into the Sphagnum moss it had to grow in. It cant handle any fertilizers so i have to be careful what i add to the water to stabilize the pH.
@Bubbala @Cap_Ron @MidwestGuy @BR2

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For a Venus Flytrap I think your best bet is to use pure water. Whatever you’re adding to adjust the pH is increasing the EC/ppm of your water. It’s important to re-test EC/ppm after adjusting pH to see how much of an impact the up or down had.
Rain, R/O, or distilled is perfect for Venus Flytraps, and you cab give it to them straight without worrying about pH. The problem with having any mineral content at all in the water you give them is that it builds up over time. They won’t show signs of trouble right away, but once the minerals start to build up in the Sphagnum moss it will have a negative effect. Honestly, I’ve never even tested pH on my Venus Flytraps. Some are in Sphagnum Moss, and some are in a soil made from Sphagnum and silica sand that’s specifically for carnivorous plants. I keep them all saturated 24/7 through the entire season until I bring them in for the winter.

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Yes, i normally just use rain water on it but i am out. It needs to rain again. I supplement with Tap water when i have to.
Thanks fot the tip on the mineral build up. I only add Silica and TPS Billions and molasses when i need to add PPM to the tap water. But still, the pH up and Down will definitely cause a build up and so might the other stuff. I will take your recommendation and only use RO or rain water. Thank you!

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